Pressure-induced Pb–Pb bonding and phase transition in Pb2SnO4

Spahr, D.; Stękiel, M.; Zimmer, D.; Bayarjargal, L.; Bunk, K.; Morgenroth, W.; Milman, V.; Refson, K.; Jochym, D.; Byrne, P.J.P.; Winkler, B.

doi:10.1107/S205252062001238X

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STRUCTURAL SCIENCE
CRYSTAL ENGINEERING
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ISSN: 2052-5206

Volume 76| Part 6| December 2020| Pages 979-991

https://doi.org/10.1107/S205252062001238X

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Pressure-induced Pb–Pb bonding and phase transition in Pb₂SnO₄

^aGoethe University, Institute of Geosciences, Crystallography, Frankfurt, Germany, ^bDassault Systèmes BIOVIA, Cambridge, United Kingdom, ^cRoyal Holloway, University of London, Physics, Oxford, United Kingdom, ^dScientific Computing Department, Rutherford Appleton Laboratory, Oxford, United Kingdom, and ^eUniversity of York, Physics, Heslington, United Kingdom
^*Correspondence e-mail: d.spahr@kristall.uni-frankfurt.de

Edited by A. Katrusiak, Adam Mickiewicz University, Poland (Received 7 July 2020; accepted 8 September 2020; online 3 November 2020)

High-pressure single-crystal to 20 GPa and powder diffraction measurements to 50 GPa, show that the structure of Pb₂SnO₄ strongly distorts on compression with an elongation of one axis. A structural phase transition occurs between 10 GPa and 12 GPa, with a change of space group from Pbam to Pnam. The resistivity decreases by more than six orders of magnitude when pressure is increased from ambient conditions to 50 GPa. This insulator-to-semiconductor transition is accompanied by a reversible appearance change from transparent to opaque. Density functional theory-based calculations show that at ambient conditions the channels in the structure host the stereochemically-active Pb 6s² lone electron pairs. On compression the lone electron pairs form bonds between Pb²⁺ ions. Also provided is an assignment of irreducible representations to the experimentally observed Raman bands.

Keywords: lead stannate (Pb₂SnO₄); density functional theory; high-pressure X-ray diffraction; pressure-induced phase transition; insulator–semiconductor transition.

CCDC references: 2030954; 2030955; 2030956; 2030957; 2030958; 2030959; 2030960; 2030961; 2030962

1. Introduction

Lead stannate (Pb₂SnO₄) belongs to a family of stannates with composition M₂SnO₄, where M²⁺ = Mg, Mn, Ca, Ba, Sr, Pb. Characteristic for these stannates is that the SnO₆ octahedra either form layers by sharing corners in a plane (as in Ba₂SnO₄ and isostructural Sr₂SnO₄) or chains by sharing edges (as in Ca₂SnO₄ and Pb₂SnO₄). They represent a fascinating class of compounds and have been studied extensively as they may be suitable for a variety of applications, e.g. as photocatalysts (Qin et al., 2015 ; Dinesh et al., 2016 ), as electrode material for Li-ion batteries (Rong et al., 2006 ; Liang et al., 2016 ) or as anode-material in solar cells (Tan et al., 2007 ). Furthermore, stannates doped with rare earth elements, such as Eu, Y, Sm, have been extensively investigated regarding their use as long afterglow phosphors (Chen et al., 2005a ,b ; Yang et al., 2005 ; Yamane et al., 2008 ; Zhang et al., 2010 ; Stanulis et al., 2014 ).

Pb₂SnO₄ has been used since the 14th century as a pigment and was frequently used in oil paintings before 1750. Nowadays the pigment is named lead-tin-yellow type I [see summary by Kühn (1993 )]. Its structure at ambient conditions (Fig. 1) was first proposed to have tetragonal space group symmetry P4₂/mbc (Byström & Westgren, 1943 ; Swanson et al., 1972 ). Later, the structure has been described in the orthorhombic space group Pbam (Gavarri et al., 1981 ).

Figure 1
Structure of Pb₂SnO₄ at ambient conditions from single-crystal structure solution. A 2 × 2 × 2 supercell is shown along the c axis. The SnO₆ octahedra are shown in gray. A diagonal (3.74 Å) and a line between two opposite Pb²⁺ ions (4.11 Å) in one of the channels which run along the c axis.

In Pb₂SnO₄ the edge-sharing SnO₆-octahedra form chains along the c-direction, interconnected within the (001) planes with Pb²⁺ ions. There are channels parallel to the c axis with a diameter of ≈ 3.74 Å (Fig. 1). In Pb₂SnO₄ the Pb ions form the apex of a trigonal pyramid, i.e. there are only three short Pb—O distances. This points towards the presence of a stereochemically active lone electron pair. In contrast, in Ca₂SnO₄, where edge-sharing SnO₆ octahedra also form chains, the Ca ions have seven nearest neighbors forming an irregular polyhedron.

At ambient conditions, the structure of Pb₂SnO₄ closely resembles that of the mineral minium (Pb₂PbO₄), which crystallizes at ambient conditions in the tetragonal space group P4₂/mbc. In Pb ₂²⁺Pb⁴⁺O₄, the Pb⁴⁺ atoms are octahedrally coordinated. Pb₂PbO₄ has channels with a diameter of ∼3.8 Å (Gavarri & Weigel, 1975 ). Pb₂PbO₄ undergoes a temperature-induced phase transition below 170 K to space group Pbam (Gavarri et al., 1978 ), so that Pb₂SnO₄ and Pb₂PbO₄ are isostructural at low temperatures, as the former shows no temperature-induced phase transition between 5 K and 300 K (Gavarri et al., 1981). For Pb₂SnO₄ the deviation from tetragonal symmetry remains small in this temperature range Δab = a − b = 0.0125 (6) Å at 300 K, Δab = 0.0139 (6) Å at 5 K].

Dinnebier et al. (2003 ) found that Pb₂PbO₄ undergoes a pressure-induced phase transition from space group P4₂/mbc at ambient pressure to space group Pbam between 0.11 and 0.3 GPa and a second transition between 5.54 and 6.58 GPa to another orthorhombic phase, also having space group Pbam but with half the length of the c axis. Increasing pressure leads to an anisotropic compression of the a and b axes, with Δab ∼ 0 Å at ambient conditions to Δab ∼ 0.9 Å at 0.6 GPa and Δab ∼ 2.9 Å at 6.7 GPa.

The objective of this study was to characterize pressure-induced changes in structure–property relations of Pb₂SnO₄ at high pressures, as it was expected that by analogy with Pb₂PbO₄ the compound would undergo phase transitions and offer insight into the high-pressure behavior of stereochemically active lone electron pairs.

2. Experimental details

2.1. Sample synthesis

2.1.1. Solid-state synthesis

Temperatures between 923 K and 1173 K have been used for the synthesis of Pb₂SnO₄ powder by solid-state reaction (Gavarri et al., 1981; Hashemi et al., 1992 ; Clark et al., 1995 ; Chen et al., 2000 ; Hradil et al., 2007 ; Pelosi et al., 2010 ; Denisov et al., 2012 ; Agresti et al., 2016 ). For our experiments we chose a synthesis temperature of 1123 (1) K, in order to avoid the presence of PbSnO₃ which decomposes above 1073 K and to prevent decomposition of Pb₂SnO₄ which is expected to occur above 1173 K (Xing et al., 2004 ).

The starting materials were analytical grade and used as purchased: PbO (99.9+% purity, Sigma-Aldrich Chemie, Darmstadt) and SnO₂ (99.9% purity, Alfa Aesar, Karlsruhe). Starting materials were mixed in stoichiometric proportions and ground in an agate mortar. The resulting mixture was pressed to 5 mm-sized pellets with an Across International Desktop pellet press at a pressure of 6 (1) Kbar. The pellets were placed in corundum crucibles with lids, transferred into a Nabertherm L08/14 muffle furnace, heated up to 1123 (1) K and annealed for 24 h. The samples were cooled down to ambient temperature by switching off the power supply. After the synthesis the pellets were ground again and the synthesis process was repeated two times.

2.1.2. Hydrothermal synthesis

Pb₂SnO₄ single crystals were hydrothermally grown in autoclaves according to a prescription by Wu et al. (1999 ), following the reaction

$[\eqalignno{&2({\rm CH}_{3}{\rm COO})_{2}{\rm Pb}\,\, +\,\, {\rm Na}_{2}{\rm SnO}_{3}\,\, +\,\, 2{\rm NaOH}\rightarrow\cr & \,\,\,\,\,\,\,\,\,\,\,\,{\rm Pb}_{2}{\rm SnO}_{4}\downarrow \,\,+ \,\,4{\rm CH}_{3}{\rm COONa} + {\rm H}_{2}{\rm O}. &(2)}]$

We used analytical grade Pb(CH₃COO)₂·3H₂O (99.5% purity, Merck, Darmstadt), Na₂SnO₃·3H₂O (98% purity, Alfa Aesar, Karlsruhe) and NaOH (99% purity, Merck, Darmstadt). The starting materials were dissolved separately in double distilled water to obtain solutions with 0.34 mol l⁻¹ [Pb(CH₃COO)₂], 0.16 mol l⁻¹ (Na₂SnO₃) and 2.0 mol l⁻¹ (NaOH) concentration. First the Na₂SnO₃ and subsequently the NaOH solution were added dropwise to the Pb(CH₃COO)₂ solution while continuously stirring at ambient temperature. The resulting suspension was transferred into a 60 ml Teflon cup which was filled up to 60% of its volume and was then placed in stainless steel autoclaves. The autoclaves were heated up to 503 (1) K for 48 h, afterwards they were slowly cooled down to 298 (1) K within 72 h. The precipitate was recovered by vacuum filtration, washed with distilled water repeatedly and dried at 333 (1) K in an oven.

2.2. Sample characterization

2.2.1. X-ray powder diffraction at ambient pressure

The powder samples obtained from solid-state synthesis were characterized with a PANalytical X'Pert Pro powder diffractometer with Bragg–Brentano geometry and a PANalytical PIXcel^3D detector. The diffractometer was equipped with a copper X-ray tube and a Johansson monochromator. The measurements were performed using Cu Kα1 radiation and 0.25° fixed divergence slits. The samples were measured in the range of 10° < 2θ < 90° with a scan speed of 0.036° min⁻¹. The instrument parameters were refined using a measurement on a high purity (99.999%) Si-standard. Powder samples were mounted on an oriented Si single-crystal sample holder after grinding them in an agate mortar. Crystal structure refinements, based on the Rietveld method (Rietveld, 1969 ), were carried out using the software package GSAS-II (Toby & Von Dreele, 2013 ).

2.2.2. X-ray single-crystal diffraction at ambient pressure

Hydrothermally synthesized crystals were employed for the single-crystal diffraction experiments at ambient conditions. Measurements were carried out on an Oxford Instruments Xcalibur four-circle diffractometer with Kappa geometry and a Sapphire3 charge-coupled-device (CCD) detector. The diffractometer was equipped with a molybdenum X-ray tube and graphite single-crystal monochromator. The samples were measured with Mo Kα radiation. We measured a full sphere up to a resolution of 0.75 Å⁻¹ and an exposure time of 120 s per frame. The crystals were mounted with Apiezon N grease on the tip of a glass capillary. Crystals of approximate dimensions 80 µm × 30 µm × 30 µm were centered in an X-ray beam of diameter 500 µm. The reflections were indexed and integrated using the CrysAlisPRO (v. 39.46) program (Agilent, 2014 $[Agilent (2014). CrysAlis PRO. Now Rigaku Oxford Diffraction, Yarnton, England.]$ ). The structure solution was performed with SUPERFLIP (Palatinus & Chapuis, 2007 ) and the refinement with the software package JANA2006 (Petricek et al., 2014 ).

2.2.3. High-pressure experiments

All high-pressure experiments were carried out using Boehler–Almax-type diamond anvil cells (Boehler, 2006 ). Depending on the target pressure of the experiments we used culet sizes between 250 µm and 350 µm and tungsten or rhenium as gasket material. Samples were placed in holes in the gasket having diameters between 100 µm and 180 µm. The gaskets were pre-indented to 40–50 µm and the holes were drilled by a custom-built laser setup. We used argon below 3 GPa for the powder diffraction and neon for all other experiments as pressure-transmitting media in pressure ranges where they provide a quasi-hydrostatic environment (Klotz et al., 2009 ). Pressure was determined by measuring the ruby fluorescence shift. We assume an error of 2% for the pressure determination in the quasi-hydrostatic conditions present in our experiments (Dewaele et al., 2004 , 2008 ).

2.2.4. High-pressure synchrotron X-ray diffraction

High-pressure diffraction data were collected at the synchrotron PETRA III (DESY) in Hamburg, Germany on the extreme conditions beamline P02.2 (Liermann et al., 2015 ). We used a Perkin Elmer XRD1621 detector and wavelengths of 0.2887 Å and 0.2906 Å for data acquisition. The beam size was 2 µm (H) × 2 µm (V) (FWHM) obtained using a Kirkpatrick–Baez mirror for the powder diffraction experiments and 9 µm (H) × 3 µm (V) (FWHM) obtained using compound refractive lenses for the single-crystal diffraction measurements.

The powder samples were measured for 10 s while rotating them around a rotation axis perpendicular to the beam by ±10° to improve the counting statistics. For calibrating the detector parameters and the detector to sample distance we measured a CeO₂ powder standard. We used the program DIOPTAS (Prescher & Prakapenka, 2015 ) to integrate and calibrate the diffraction patterns.

For single-crystal diffraction the samples were rotated around a rotation axis perpendicular to the beam by ±33°. Frames were collected in 0.5° steps with 0.5 s acquisition time per frame. Pt-filters were used to reduce the primary intensity to prevent oversaturation of the detector. The diffractometer/detector geometry was calibrated by measuring an enstatite single crystal. Data treatment and crystal structure refinement were performed in a similar manner as for ambient-pressure single-crystal diffraction data.

The lattice parameters from the high-pressure powder diffraction data were obtained applying the Le Bail method (Le Bail et al., 1988 ), using the software package GSAS-II (Toby & Von Dreele, 2013). The bulk modulus from the high-pressure powder data was obtained by using the EoSFit7-GUI software package (Gonzalez-Platas et al., 2016 ), fitting a second-order Birch–Murnaghan equation of state (EoS) (Murnaghan, 1944 ; Birch, 1947 ) to the unit-cell volume.

2.2.5. High-pressure electrical resistance measurements

High-pressure resistance measurements were carried out in diamond anvil cells (Fig. 2) using a mixture of epoxy resin and Al₂O₃ as pressure-transmitting medium. We assume an error of the pressure determination due to non-hydrostatic conditions of 6% (Mao et al., 1986 ). We performed both two-point and four-point measurements using a Keithley DMM7510 multimeter for the data collection as described in Zimmer et al. (2018 ).

Figure 2
Pb₂SnO₄ crystal connected to gold wires in a diamond anvil cell for resistance measurements using the four-point probes method at 4.3 (3) GPa.

2.2.6. Raman spectroscopy

Raman spectroscopy was carried out with a custom set-up described in detail in Bayarjargal et al. (2018 ). We used an OXXIUS S.A. LaserBoxx LMX532 laser (λ = 532.14 nm) and a Princeton Instruments ACTON SpectraPro 2300i spectrograph equipped with a Pixis256E CCD camera. All Raman spectra were background corrected with the software package Fityk (Wojdyr, 2010 ). High-pressure Raman spectroscopy was carried out in diamond anvil cells, similar to the high-pressure synchrotron X-ray diffraction experiments.

2.2.7. Scanning electron microscopy

We used a Phenom World ProX desktop SEM for the acquisition of electron backscatter images (BSE) on single crystals and powder samples. Furthermore, energy-dispersive X-ray spectroscopy (EDX) measurements for a semi-quantitative characterization of the composition were carried out on single crystals and powder samples. The samples were mounted without coating on aluminium stubs using sticky carbon tape. They were measured under low-vacuum conditions to reduce charging effects on the sample with an acceleration voltage of 10 KV for imaging and 15 KV for EDX measurements.

3. Computational details

First-principles calculations were carried out within the framework of density functional theory (DFT) (Hohenberg & Kohn, 1964 ), employing the Perdew–Burke–Ernzerhof (PBE) exchange-correlation function (Perdew et al., 1996 ) and the plane wave/pseudopotential approach implemented in the CASTEP (Clark et al., 2005 ) simulation package. `On the fly' norm-conserving or ultrasoft pseudopotentials generated using the descriptors in the CASTEP data base were employed in conjunction with plane waves up to a kinetic energy cutoff of 990 eV or 630 eV, for norm-conserving and ultrasoft pseudopotentials, respectively. The accuracy of the pseudopotentials is well established (Lejaeghere et al., 2016 ). A Monkhorst–Pack (Monkhorst & Pack, 1976 ) grid was used for Brillouin-zone integrations with a distance of < 0.023 Å⁻¹ between grid points. Convergence criteria included an energy change of < 5 × 10⁻⁶ eV atom⁻¹ for scf-cycles, a maximal force of < 0.008 eVÅ⁻¹, and a maximal component of the stress tensor < 0.02 GPa. Phonon frequencies were obtained from density functional perturbation theory (DFPT) calculations. Raman intensities were computed using DFPT with the `2n+1' theorem approach (Miwa, 2011 ) and a scissor operator of 5 eV. It should be stressed that all calculations are carried out in the athermal limit, i.e. the influence of temperature and zero-point motion is not taken into account.

4. Results

4.1. Synthesis

We synthesized Pb₂SnO₄ powder by solid-state reaction. The powder is slightly yellow at ambient conditions and does not show any distinct growth morphology [Fig. 3(a)]. From hydrothermal synthesis we obtained crystals with 50–150 µm lengths. Some crystals form aggregates, but many of them show a tetragonal crystal habit and idiomorphic crystal faces [Fig. 3b]. Most of those crystals are colorless. The morphology of the single crystals is similar to that observed in an earlier study (Wu et al., 1999).

Figure 3
SEM image of slightly yellow Pb₂SnO₄ powder obtained by solid-state reaction (a) and of a colorless Pb₂SnO₄ crystal from hydrothermal synthesis (b).

The chemical composition obtained from the EDX measurements on the powders and single crystals do not substantially differ from the expected chemical composition (nominal versus EDX in at.%): PbO: 67/70 (4) and SnO₂: 33/30 (3) for the powders from the solid-state reaction and PbO: 67/71 (4) and SnO₂: 33/29 (3) for the single crystals from the hydrothermal synthesis. Furthermore, no impurities from other elements were observed in the EDX spectra.

4.2. Powder diffraction at ambient pressure

No secondary phase was detected by X-ray powder diffraction within the experimental detection limits of ∼3%. The phase purity of the powder was also confirmed by Rietveld refinement (Fig. 4). The refinement of the powder data can be carried out in two space groups. A refinement in the tetragonal space group P4₂/mbc (wR = 12.1%) as well as in its orthorhombic subgroup Pbam (wR = 10.7%) with Z = 4 gave a satisfactory fit of the structural model to the diffraction data. Table 1 summarizes the diffraction data for Pb₂SnO₄ at ambient conditions. The refined crystallographic parameters for both space groups are also in good agreement with earlier studies (Swanson et al., 1972; Gavarri et al., 1981).

Table 1
Crystallographic data of Pb₂SnO₄ at ambient conditions obtained by single-crystal structure solution, Rietveld refinement on powder data and DFT-based calculations in comparison to data from Swanson et al. (1972) and Gavarri et al. (1981)

	This study (tetragonal)			This study (orthorhombic)			Swanson et al. (1972)†	Gavarri et al. (1981)‡§
	Single crystal	Powder	DFT	Single crystal	Powder	DFT	Powder	Powder
Crystal system	Tetragonal			Orthorhombic			Tetragonal	Orthorhombic
Space group	P4₂/mbc (No. 135)			Pbam (No. 55)			P4₂/mbc (No. 135)	Pbam (No. 55)
a (Å)	8.7276 (2)	8.7387 (1)	8.9184	8.7288 (3)	8.7425 (2)	8.9298	8.7371 (4)	8.7215 (3)
b (Å)	–	–	–	8.7263 (3)	8.7330 (2)	8.9103	–	8.7090 (3)
c (Å)	6.2970 (2)	6.3075 (1)	6.4713	6.2969 (2)	6.3068 (2)	6.4715	6.307 (1)	6.2919 (3)
Δab (Å)	0	0	0	0.0025 (4)	0.0095 (3)	0.0195	0	0.0125 (6)
V (Å³)	479.65 (2)	481.67 (2)	514.71	479.64 (3)	481.51 (4)	514.92	481.46	477.90 (4)
ρ (g cm⁻³)	8.268	8.234	7.705	8.269	8.236	7.702	8.237	8.323
R_int (%)	4.2	–	–	4.1	–	–	–	–
No. of unique reflections	349	109	–	679	216	–	–	≈ 800
No. of refined parameters	22	24	–	40	33	–	–	47
Refinement
R (%)	2.1	8.8	–	2.5	7.7	–	–	6.9
wR (%)	2.3	12.1	–	2.6	10.7	–	–	–
GOF	1.3	2.5	–	1.2	2.2	–	–	–
λ (Å)	0.71073	1.54056	–	0.71073	1.54056	–	1.54056	1.384 (2)

†ICDD No. 00-024-0589.
‡ICDD No. 01-075-1846.
§Neutron diffraction.

Figure 4
Rietveld refinements on a Pb₂SnO₄ powder sample from solid-state synthesis at ambient conditions in space group P4₂/mbc (a) and Pbam (b) using λ = 1.54056 Å. Reflection positions are indicated by tickmarks and the residuals between measurement and refinement are shown by the blue line.

The deviation from a tetragonal metric in the orthorhombic refinement [Δab = 0.0095 (3) Å] is very small and in good agreement with the value obtained by neutron powder diffraction data from Gavarri et al. (1981) [Δab = 0.0125 (6) Å]. Furthermore, no peak splitting was observed in the diffraction data. The refinement in space group Pbam shows a slightly lower wR value compared to the refinement in space group P4₂/mbc. This is caused by the higher reflection to parameter ratio (6.5:1 for Pbam in contrast to 4.5:1 for P4₂/mbc).

4.3. Single-crystal diffraction at ambient pressure

The structure solution for Pb₂SnO₄ by Gavarri et al. (1981) was performed on neutron powder data; here we carried out the first single crystal data collection and structure refinements. High-quality crystals from our hydrothermal synthesis are colorless at ambient conditions and suitable for single-crystal X-ray diffraction.

Similar to the results obtained from the powder diffraction data at ambient conditions, the refinement of the single crystal data gives very satisfactory results in two space groups. Both structure refinements in space group P4₂/mbc (wR = 2.3%) and in space group Pbam (wR = 2.6%) gave convincing structural models (Table 1), which are in good agreement with the results of earlier studies (Swanson et al., 1972; Gavarri et al., 1981). Table 2 summarizes the atomic positions and anisotropic displacement parameters of Pb₂SnO₄ for the refinements in both space groups.

Table 2
Atom positions and anisotropic displacement parameters of Pb₂SnO₄ in space groups P4₂/mbc and Pbam from single-crystal structure refinement

Lattice parameters a, b, c in Å and atomic displacement parameters U_ij in Å².

	Atom	Site	a	b	c	U_eq	U₁₁	U₂₂	U₃₃	U₁₂	U₁₃	U₂₃
P4₂/mbc	Pb	8h	0.16055 (5)	0.14197 (5)	0.5	0.0223 (1)	0.0225 (3)	0.0205 (3)	0.0239 (3)	0.0014 (2)	0	0
	Sn	4d	0.5	0	0.75	0.0181 (2)	0.0196 (3)	0.0196 (3)	0.0152 (5)	0.0015 (4)	0	0
	O1	8h	0.0973 (8)	0.3750 (8)	1.0	0.020 (2)	0.024 (4)	0.018 (4)	0.019 (4)	−0.003 (3)	0	0
	O2	8g	0.3344 (6)	0.1656 (6)	0.75	0.025 (2)	0.027 (3)	0.027 (3)	0.022 (4)	0.003 (3)	0.004 (2)	0.004 (2)
Pbam	Pb1	4g	0.16058 (5)	0.14191 (5)	0.5	0.0222 (2)	0.0226 (3)	0.0201 (3)	0.0239 (3)	0.0014 (2)	0	0
	Pb2	4h	0.35797 (5)	0.33984 (5)	1.0	0.0223 (2)	0.0226 (3)	0.0201 (3)	0.0239 (3)	0.0014 (2)	0	0
	Sn	4f	0.5	0	0.7502 (2)	0.0181 (3)	0.0196 (4)	0.0195 (5)	0.0152 (4)	−0.0015 (3)	0	0
	O1	4h	0.0979 (8)	0.37653 (8)	1.0	0.021 (3)	0.023 (5)	0.019 (5)	0.021 (5)	−0.002 (4)	0	0
	O2	8i	0.3344 (6)	0.16559 (6)	0.752 (1)	0.019 (3)	0.016 (4)	0.023 (5)	0.019 (5)	−0.002 (4)	0	0
	O3	4g	0.1264 (6)	0.4381 (6)	0.5	0.025 (2)	0.022 (4)	0.032 (4)	0.022 (4)	−0.003 (3)	−0.003 (3)	0.004 (3)

The anisotropic displacement parameters do not differ substantially between the structure refinements in space group P4₂/mbc and Pbam. Lowering of the symmetry from P4₂/mbc to Pbam space group induces a splitting of the Wyckoff positions of the Pb1 and O1 atoms with 8h → 4g + 4h, but a detailed analysis showed no significant change in interatomic distances between the two refinements.

4.4. DFT calculations at ambient pressure

We cross-checked our experimental results with those of DFT-based calculations in both possible space groups for Pb₂SnO₄ (Tab. 1). Our DFT-based calculations reproduce the experimental diffraction data satisfactorily with an overestimation of the unit-cell lengths by <3% due to the well established `underbinding' in DFT-GGA-PBE calculations. The DFT calculations carried out here provide structural and physical parameters in the athermal limit. As has been discussed in the introduction, structurally closely related Pb₂PbO₄ undergoes a tetragonal $[\leftrightarrow]$ orthorhombic phase transition at 170 K, so it is actually problematic to neglect temperature in DFT studies of this system. The DFT-based calculations gave the same total energy within the numerical accuracy for the orthorhombic and the tetragonal structure.

Fig. 5 shows an isosurface of the electron density difference, i.e. shows charge accumulation with respect to the electron density obtained by overlapping non-interacting atomic densities.

Figure 5
Isosurface of the electron density difference at 0.03 e Å⁻¹. Sn atoms, oxygen atoms and lead atoms are represented by violet, red and gray spheres, respectively. The yellow circle highlights a channel running parallel to [001], which hosts the 6s² stereochemically active lone electron pairs of the Pb²⁺ ions, which appear as umbrella shaped surfaces.

Clearly discernible are the stereochemically-active 6s² lone electron pairs of the Pb²⁺ ions, which appear in electron density difference isosurfaces as umbrella shaped objects (Friedrich et al., 2010 ). These electron pairs are located in the channels of the structure.

4.5. High-pressure single-crystal diffraction

We performed high-pressure single crystal X-ray diffraction measurements on Pb₂SnO₄ crystals up to 21.0 (4) GPa and solved and refined the crystal structure at numerous pressures (Table 3). From the single crystal data we found that on pressure increase the unit cell of Pb₂SnO₄ is immediately strained and Δab increases from 0.0025 (4) Å at ambient pressure to its maximum of 2.799 (1) Å at 12.4 (3) GPa. After a pressure increase above ∼0.5 GPa the structure of Pb₂SnO₄ cannot be described in space group P4₂/mbc anymore and only a refinement in space group Pbam is satisfactory. At 7.8 (2) GPa (wR = 14.0%) and 10.0 (2) GPa (wR = 18.5%) the refinements of the structure in the space group Pbam yield increasingly worse reliability factors, but attempts to improve the description of the data by changing the structural model to another space group were unsuccessful.

Table 3
Selected crystallographic data of Pb₂SnO₄ obtained between ambient conditions and 21 GPa by synchrotron-based single-crystal structure refinements

The crystal was colorless at ambient conditions and had approximate dimensions 80 µm × 30 µm × 30 µm.

p (GPa)	0.0001†		2.0 (1)	5.5 (1)	7.8 (2)	10.0 (2)	12.4 (3)	15.2 (3)	21.0 (4)
Space group	P4₂/mbc (No. 135)	Pbam (No. 55)	Pbam (No. 55)				Pnam (No. 62)
a (Å)	8.7372 (2)	8.7397 (3)	9.1901 (7)	9.3799 (7)	9.3641 (6)	9.3169 (6)	9.2484 (8)	9.1830 (6)	9.0691 (6)
b (Å)	–	8.7348 (3)	7.9508 (3)	7.2103 (3)	6.8646 (6)	6.6337 (6)	6.4498 (9)	6.4046 (6)	6.3282 (6)
c (Å)	6.3048 (2)	6.3047 (2)	6.2893 (7)	6.3250 (7)	6.3553 (2)	6.3808 (2)	6.4096 (2)	6.3727 (2)	6.3110 (2)
Δab (Å)	0	0.0049 (4)	1.2393 (8)	2.1696 (8)	2.4995 (9)	2.6832 (9)	2.799 (1)	2.7784 (9)	2.7409 (9)
V (Å³)	481.30 (2)	481.30 (3)	459.55 (6)	427.77 (6)	408.52 (5)	394.37 (5)	382.33 (6)	374.80 (4)	362.20 (4)
ρ (g cm⁻³)	8.240	8.240	8.630	9.271	9.708	10.056	10.373	10.582	10.950
R_int (%)	2.0	1.7	1.7	1.5	3.7	7.4	1.4	1.6	1.7
No. of unique reflections	770	1503	1011	898	1085	1004	814	814	813
No. of refined parameters	22	40	40	40	29‡	26‡	38	38	38
R (%)	2.0	2.2	2.3	2.1	8.7	13.9	1.9	2.0	2.4
wR (%)	2.7	2.9	2.9	2.9	14.0	18.5	2.3	2.7	2.9
GOF	1.8	1.7	1.4	1.6	5.1	6.0	1.2	1.4	1.4

†Opened diamond anvil cell after pressure release.
‡Anisotropic refinement of atomic displacement parameters was unsuccessful.

On further pressure increase we observed that Pb₂SnO₄ undergoes a phase transition from the orthorhombic space group Pbam (No. 55) to Pnam (No. 62) between 10 GPa and 12 GPa. At 12.4 (3) GPa (wR = 2.3%), the refinement in the high-pressure space group Pnam is convincing. We chose the unconventional Pnam setting of space group No. 62 in order to facilitate a comparison to the low-pressure structure. A symmetry check with the PLATON package (Spek, 2003 ) was carried out to confirm the space group symmetry.

After pressure release we measured the same crystal in an opened diamond anvil cell at ambient conditions. The structure refinement shows that the pressure-induced straining of the unit cell and the pressure-induced phase transition is fully reversible on pressure release (Table 3).

4.6. High-pressure powder diffraction

The high-pressure X-ray powder data complement the single-crystal data, as they have been measured for pressures up to 50 (1) GPa. We used the results from the single crystal refinement on Pb₂SnO₄ as starting model for the refinements of the powder diffraction data. Fig. 6 shows a Rietveld refinement of data collected at 12.0 (2) GPa, close to the pressure-induced structural phase transition. The refinement was carried out in space group Pnam. The anisotropic displacement parameters of the oxygen atoms were constrained to be identical and we applied restraints to ensure that the Sn—O bond distances are ∼2 Å. The high background is caused by diamonds and the pressure transmitting medium. The agreement between the experimental data and the structural model is convincing. The results obtained from the refinements of the powder data are in good agreement with the single crystal data collected up to 21 GPa.

Figure 6
Rietveld refinement of Pb₂SnO₄ at 12.0 (2) GPa in space group Pnam (wR = 2.7%) using λ = 0.2906 Å. Reflection positions are indicated by tickmarks and the residuals between measurement and refinement are shown by the blue line. Diamond and neon reflections were masked before data integration.

4.7. Deformation of the Pb₂SnO₄ unit cell

Fig. 7 shows the behavior of the Pb₂SnO₄ lattice parameters between ambient conditions and 30 GPa from single crystal and powder diffraction data in comparison to DFT-based calculations. Based on the single crystal and powder diffraction data we observed that the pressure dependence of the unit-cell parameters are very different up to pressures of ∼12 GPa. In this pressure regime, the a axis expands on pressure increase, the b axis shrinks, and the c axis remains essentially unchanged. This observation is supported by the DFT-based calculations.

Figure 7
Pressure-dependent behavior of the Pb₂SnO₄ lattice parameters, from single-crystal diffraction (blue), powder diffraction (red) and DFT calculations (black). The lattice parameter a is shown with black squares, b with filled circles and c with red diamonds.

4.8. Description of the high-pressure crystal structure

Fig. 8 shows the evolution of the crystal structure of Pb₂SnO₄ with increasing pressure. The pressure-induced elongation of the a axis and the compression in the b direction and the concomitant rearrangement of the Pb ions before the phase transition can clearly be observed.

Figure 8
Pb₂SnO₄ crystal structure viewed along the c axis at 2.0 (1) GPa (a), 7.8 (2) GPa (b) and 12.4 (3) GPa (c). Structure viewed along the a axis at 12.4 (3) GPa (d). 2 × 2 × 2 supercells are shown and the SnO₆ octahedra are illustrated in gray.

The pressure-dependence of the Pb–Pb and Sn—O distances in Pb₂SnO₄ are shown in Fig. 9. We observed that the SnO₆ octahedra behave as quasi-rigid units in the crystal structure. The Sn—O bond lengths in the SnO₆ octahedra remains approximately constant (∼2 Å) and are only slightly decreasing with increasing pressure. At ambient conditions the SnO₆ octahedra have a volume of V_SnO₆ = 11.9 Å³ which is decreasing to V_SnO₆ = 11.1 Å³ at 21.0 (4) GPa. The distance between the opposite Pb²⁺ ions, forming the channels at ambient conditions (Fig. 1), is decreasing by 1 Å with increasing pressure from ∼4.1 Å at ambient conditions to ∼3.1 Å at 12.4 (3) GPa. After the phase transition the Pb–Pb distance is almost independent of pressure.

Figure 9
Pb—Pb and Sn—O distances with increasing pressure from single-crystal diffraction (filled square) and DFT-based calculations (filled circle). Lines represent fits to the experimental data points.

The experimental finding of a phase transition was also supported by DFT-based calculations. The calculations imply, based on the enthalpy difference $[\Delta H = H_{{Pbam}}-H_{{Pnam}}]$ , that the phase transition from space group Pbam to Pnam occurs just below 10 GPa. The experimentally determined transition pressure and the results from the DFT-based calculations are therefore in good agreement.

The DFT calculations show a rather peculiar behavior of the stereochemically active lone electron pairs. While it is well established that such lone electron pairs may persist at high pressures [e.g. Friedrich et al. (2010)] Fig. 10 shows that in Pb₂SnO₄ the lone electron pairs overlap on increasing pressure, i.e. there is bond formation along the Pb—Pb contacts both within the (001) planes and along the c direction.

Figure 10
Electron density difference maps obtained by DFT calculations of the pressure induced evolution of the stereochemically active lone electron pairs (highlighted by white circles) show that at high pressures there is a charge accumulation along the Pb—Pb contacts, i.e. Pb—Pb bonds have been formed by transferring 6s electrons of a Pb atom into empty 6p orbitals of a Pb atom <3 Å away. 2 × 2× 2 supercells are shown along the c axis.

The formation of Pb—Pb bonds has been discussed earlier [see e.g. reviews by Fischer & Power (2010 ) and Nagase (2013 )] in diplumbenes, which have Pb—Pb bonds with bond distances of 2.9–4.1 Å. In the present case, the change in the electron density suggests the formation of dative bonds between the Pb²⁺ ions, i.e. bonds due to the interaction of the stereochemically active lone electron pairs of the donor atom with unoccupied orbitals of the acceptor atom. A Mulliken population analysis shows that the Pb 6p orbitals are filled slightly more on bond formation and the bond population between neighboring Pb²⁺ ions rises up to 0.28 e Å⁻³ at 80 GPa.

4.9. Bulk modulus of Pb₂SnO₄

We used the X-ray powder diffraction data to obtain the unit cell volume of Pb₂SnO₄ from ambient conditions up to 50 (1) GPa (Fig. 11). These data sets were used to compute the values of the bulk modulus K for the low-pressure phase (Pbam) and the high-pressure phase (Pnam). We fitted a second-order Birch–Murnaghan equation of state to unit cell volume data up 10.4 (2) GPa for the low-pressure structure. The ambient-pressure volume V₀ was not refined due to the limited data range for this structure and fixed to the volume obtained from ambient-pressure X-ray diffraction. For the high-pressure phase we fitted a second-order Birch–Murnaghan equation of state to the experimental data between 12.0 (2) GPa and 50 (1) GPa, refining the ambient-pressure volume V₀ also. Table 4 lists the experimental values of K for both phases. The bulk moduli of the ambient-pressure phase [K_Pbam = 36 (2) GPa] and the high-pressure phase (K_Pnam = 117 (6) GPa) differ significantly.

Table 4
Bulk modulus of the low- and high-pressure structures of Pb₂SnO₄ from X-ray powder diffraction

	K_exp(GPa)	V₀ Å³)†
Pbam	36 (2)	479.64 (3)
Pnam	117 (6)	420 (3)

†Constrained to the value obtained from ambient-pressure X-ray diffraction.

Figure 11
Pressure dependence of the unit-cell volume of Pb₂SnO₄ from X-ray powder diffraction data. The second-order Birch–Murnaghan equation of state fitted to the experimental data for the low-pressure phase is shown in blue and for the high-pressure phase in red.

4.10. Resistance measurements

4.10.1. Calibrating the experimental set-up

We performed electrical resistance measurements as a function of pressure in diamond anvil cells. These measurements were calibrated by measuring pure silicon (99.999% purity, Alfa Aesar). At ambient pressure silicon crystallizes in space group $[Fd{\bar 3}m]$ (No. 227) (Cohen & Chelikowsky, 1989 ). Between 8 GPa and 12.5 GPa silicon undergoes a phase transition into the β-Sn structure with space group I4₁ (No. 141) (Garg et al., 2004 ; Olijnyk et al., 1984 ; Weinstein & Piermarini, 1975 ; Hu & Spain, 1986 ; Gupta & Ruoff, 1980 ; Hu et al., 1986 ; Yin & Cohen, 1982 ; McMahan & Moriarty, 1983 ; Chang & Cohen, 1985 ; Mizushima et al., 1994 ), accompanied by a decrease of the electrical resistance by ∼10⁷ (Garg et al., 2004; Minomura & Drickamer, 1962 ).

Our measurements from ambient conditions to 21 (1) GPa show a change of the resistance of > 10⁶ (Fig. 12). The resistance decreases by 10^4.5 within ∼2.5 GPa in the region of the phase transition from Si-I to Si-II and we determined a transition pressure of 8.4 (5) GPa. Garg et al. (2004) measured a decrease of the resistance by 10^4.5 within ∼5 GPa and a transition pressure of 10.2 GPa using mylar embedded Al₂O₃ as pressure transmitting medium. In comparison to Garg et al. (2004) the phase transition occurs in a much narrower pressure-range in our experiments, but at slightly lower pressures. The transition pressure obtained here is in good agreement with the data from Hu et al. (1986) who found that the phase transition occurs at lower pressures of ∼8.5 GPa in a non-hydrostatic environment in comparison to a transition pressure of 11.3 (2)–12.5 (2) GPa for quasi-hydrostatic conditions. Gupta & Ruoff (1980) found a sensitivity of the Si-I to Si-II phase transition to uniaxial stress and observed a change in the pressure-dependent resistance at 8 GPa by applying uniaxial stress along [111]. In summary, these calibration measurements show that our set-up allows us to accurately measure pressure-induced changes in the resistance but the sample environment is not hydrostatic.

Figure 12
Electrical resistance measurements on Si for calibrating and testing the experimental set-up as function of pressure using the four-point probe method up to 21 (1) GPa in comparison to data of Garg et al. (2004

4.10.2. Pressure-dependent resistance of Pb₂SnO₄

Pressure increase leads to a significant color change of Pb₂SnO₄ powder and single crystals. At ambient pressure, the crystals are colorless and the powder is lightly yellow. With increasing pressure the light yellow powder at ambient pressure and the single crystals became yellow (∼3 GPa), red (∼6 GPa) and brown (∼8 GPa). On further pressure increase the sample becomes opaque (Fig. 13). All pressure-induced color changes are fully reversible on pressure release without hysteresis.

Figure 13
Pressure-dependent color change of Pb₂SnO₄ between 0 GPa and 17 (1) GPa in a diamond anvil cell.

The change in color is caused by a change in the absorption of visible light by the sample, indicative of a decrease in the band gap. Electrical resistance measurements were carried out between ambient pressure and 48 (3) GPa using two-point and four-point measurements (Fig. 2). Below 14.2 (9) GPa the electrical resistance was above the detection limit of our experimental set-up (10 × 10⁹ Ω).

The electrical resistance of Pb₂SnO₄ decreases by at least six orders of magnitude when the pressure is increased from ambient to ∼40 GPa (Fig. 14). Due to the limitations of our experimental setup we were not able to determine the resistance of the sample across the structural phase transition. An extrapolation of the resistance to ambient pressure [using f(x) = A₁·exp(−x/f₁) + y₀] suggests a resistivity > 10¹⁴ Ωm for Pb₂SnO₄, similar to insulators such as quartz or corundum. The results from the two-point probes and the four-point probes method are mutually consistent, as it is expected that two-point measurements will yield systematically higher values due to the additional contact resistance of the junction between the sample and the wires.

Figure 14
Electrical resistance measurements on Pb₂SnO₄ as function of pressure using the two-point probes and the four-point probes method (black). f(x) shows an exponential fit to the two-point probes measurement. Due to the limitation of the Keithley instrument employed, high resistances could not be observed. The DFT-calculated band gap is shown in red.

We calculated the band gap energy E_g between 0 and 50 GPa by DFT-based calculations and present it together with the electrical resistance measurement (Fig. 14). The results of these calculations indicate that the band gap is closing between 40 GPa and 50 GPa. However, it is well established that DFT-GGA-PBE calculations underestimate the band gap energy by up to 50% and while the pressure-dependence of the experimentally determined electrical resistance and predicted band gap energy is similar, a quantitative evaluation would require more advanced model calculations. The closing of the band gap is also consistent with the observed pressure-induced change in color.

4.11. Raman spectroscopy

Raman spectroscopy was performed on powder samples and on a single crystal. Experimentally determined ambient-pressure Raman spectra of Pb₂SnO₄ were satisfactorily reproduced by a theoretical spectrum from DFT-based calculations independent of their synthesis route [Fig. 15(a)]. The theoretical Raman spectra for structures with space group symmetry of Pbam or P4₂/mbc are almost identical, therefore both reproduced the experimental data. The experimentally obtained Raman spectra are also in good agreement with the measurements from e.g. Clark et al. (1995) or Pelosi et al. (2010).

Figure 15
Ambient-pressure Raman spectra of Pb₂SnO₄ powder and a single crystal in comparison to results from DFT-based calculations (a) and Experimental Raman spectra of a Pb₂SnO₄ single crystal at 16.0 (3) GPa in comparison to results from DFT-based calculations at 15.2 GPa carried out in space group Pnam (b). The frequencies of the calculated Raman spectrum were rescaled by 8%.

According to a factor group analysis (DeAngelis et al., 1972 ) for space group Pbam 42 modes (Γ_Raman = 12 A_g + 12 B_1g + 9 B_2g + 9 B_3g) and for space group P4₂/mbc 26 modes are Raman active (Γ_Raman = 5 A_1g + 7 B_1g + 5 B_2g + 9 E_g). We assigned irreducible representations to the observed peaks based on the DFT-based calculations in space group Pbam [Fig. 15(a)]. Table 5 shows the Raman shift of the experimental and calculated Raman modes in Pb₂SnO₄ together with the corresponding assignment to the irreducible representation from DFT-based calculations for Pbam.

Table 5
Peak positions (cm⁻¹) of selected Raman modes of Pb₂SnO₄ from experimental data and DFT-based calculations at ambient conditions together with DFT-based mode assignments to irreducible representation

Experiment	DFT	$[\Gamma _{{\rm {Raman}}}^{{Pbam}}]$
56.2	46.0	A_g
78.3	72.4, 79.7, 79.7	A_g, B_2g,3g
94.4	86.6	B_1g
112.7	102.7, 102.7	B_2g,3g
128.6	119.5	A_g
195.2	62.1, 62.9	B_2g,3g
274.7	249.1	A_g
292.0	268.6	A_g
303.9	278.9	A_g
337.1	305.2	B_1g
378.8	337.0, 337.0	B_2g,3g
457.5	425.1	A_g
508.1	467.8, 467.8	B_2g,3g
525.3	481.2, 481.2, 486.0, 490.7	B_1g,2g,3g, A_g

Fig. 15(b) shows experimental Raman data at 16.0 (3) GPa in comparison to results from DFT-based calculations at 15.2 GPa. The agreement between the peak positions from the experimental data and DFT-based calculations for the high-pressure structure with Pnam space group symmetry is convincing and all experimentally observed Raman peaks can be assigned to their irreducible representations (Γ_Raman = 12 A_g + 9 B_1g + 12 B_2g + 9 B_3g). Table 6 shows the experimental and theoretical Raman data together with the corresponding assignment to the irreducible representation for the high-pressure space group Pnam.

Table 6
Peak positions (cm⁻¹) of selected Raman modes of Pb₂SnO₄ from experimental [16.0 (3) GPa] data and DFT-based calculations (15.2 GPa) in the high-pressure space group Pnam together with DFT-based mode assignments to irreducible representation

Experiment	DFT	$[\Gamma ^{Pbam}_{\rm Raman}]$
93.1	81.2	A_g
113.8	103.1	B_1g
130.8	119.3	A_g
146.9	138.1, 138.1	A_g, B_2g
183.3	171.1	A_g
207.1	191.8	A_g
271.5	248.9, 254.0	A_g, B_3g
358.6	329.3, 330.7, 334.0	A_g, B_2g,3g
479.7	443.4	A_g
509.1	462.1, 462.5	A_g, B_2g
646.7	592.2	A_g

5. Discussion and conclusion

The ambient pressure X-ray diffraction data of Pb₂SnO₄ can be successfully refined in two space groups (P4₂/mbc or Pbam) with very similar R values. Neither Raman spectroscopy nor DFT calculations can be used to unambiguously distinguish between the two space groups. While the structure of Pb₂SnO₄ is undoubtedly very nearly tetragonal, both earlier studies (Gavarri et al., 1981) and the present experiments lead to the conclusion that there is a small deviation from P4₂/mbc and that hence the space group Pbam is the preferred choice for the structure of Pb₂SnO₄ at ambient conditions.

The high-pressure X-ray diffraction data and DFT-based calculations show a significant pressure-induced distortion from the quasi-tetragonal metric present at ambient conditions with increasing pressure. Pb₂SnO₄ with Pbam space group symmetry is stable up to 8–10 GPa, when a structural phase transition to a high-pressure structure with space group symmetry Pnam occurs. The experimentally observed structural phase transition is consistent with the results from the DFT-based calculations and Raman spectroscopic data. We observed no further phase transition of Pb₂SnO₄ up to 50 GPa.

The pressure-induced structural changes lead to a rearrangement of the Pb ions, while the chains formed by the edge-shared SnO₆ octahedra remain essentially unchanged. The high-pressure phase is stabilized by the formation of Pb—Pb bonds. The presence of the Pb—Pb bonds at high pressures has been inferred from a Mulliken analysis of the electron density obtained from DFT calculations and from electron density difference maps. Our findings are consistent with earlier results on Pb—Pb bonding based on NMR measurements (Gabuda et al., 1999 ; Dybowski et al., 2001 ), in which it was concluded that the Pb²⁺ 6p electron is involved.

The pressure-induced structural changes are accompanied by changes in the physical properties, such as a dramatic change in color and a large change in the resistivity. The experimentally obtained bulk moduli for the low- and high-pressure phase of Pb₂SnO₄ differ significantly [K_Pbam = 36 (2) GPa and K_Pnam = 117 (6) GPa]. A similar drastic change in the bulk moduli between the low and high-pressure phase has also been observed for the phase transition from phase II [K_{phase II} = 20.8 (4) GPa] to phase III [K_{phase III} = 98 (3) GPa] in structurally closely related Pb₂PbO₄ (Dinnebier et al., 2003). The pressure-induced changes in the structural and physical properties are fully reversible on pressure release.

In summary, Pb₂SnO₄ was shown to display an interesting high pressure behavior which is associated with a change of the properties of the stereochemically active lone electron pairs present at ambient conditions and the formation of Pb—Pb bonds. Studies to further characterize these bonds are currently underway.

Supporting information

CCDC references: 2030954; 2030955; 2030956; 2030957; 2030958; 2030959; 2030960; 2030961; 2030962

Crystal structure: contains datablocks global, Pb2SnO4-P42ombc-P0, Pb2SnO4-Pbam-P0, Pb2SnO4-Pbam-P1, Pb2SnO4-Pbam-P2, Pb2SnO4-Pbam-P3, Pb2SnO4-Pbam-P4, Pb2SnO4-Pnam-P5, Pb2SnO4-Pnam-P6, Pb2SnO4-Pnam-P7. DOI: https://doi.org/10.1107/S205252062001238X/xk5074sup1.cif

Structure factors: contains datablock Pb2SnO4-P42ombc-P0. DOI: https://doi.org/10.1107/S205252062001238X/xk5074Pb2SnO4-P42ombc-P0sup2.hkl

Structure factors: contains datablock Pb2SnO4-Pbam-P1. DOI: https://doi.org/10.1107/S205252062001238X/xk5074Pb2SnO4-Pbam-P1sup3.hkl

Structure factors: contains datablock Pb2SnO4-Pbam. DOI: https://doi.org/10.1107/S205252062001238X/xk5074Pb2SnO4-Pbam-P0sup4.hkl

Structure factors: contains datablock Pb2SnO4-Pbam-P2. DOI: https://doi.org/10.1107/S205252062001238X/xk5074Pb2SnO4-Pbam-P2sup5.hkl

Structure factors: contains datablock Pb2SnO4-Pbam-P3. DOI: https://doi.org/10.1107/S205252062001238X/xk5074Pb2SnO4-Pbam-P3sup6.hkl

Structure factors: contains datablock Pb2SnO4-Pbam-P4. DOI: https://doi.org/10.1107/S205252062001238X/xk5074Pb2SnO4-Pbam-P4sup7.hkl

Structure factors: contains datablock Pb2SnO4-Pnam-P5. DOI: https://doi.org/10.1107/S205252062001238X/xk5074Pb2SnO4-Pnam-P5sup8.hkl

Structure factors: contains datablock Pb2SnO4-Pnam-P6. DOI: https://doi.org/10.1107/S205252062001238X/xk5074Pb2SnO4-Pnam-P6sup9.hkl

Structure factors: contains datablock Pb2SnO4-Pnam-P7. DOI: https://doi.org/10.1107/S205252062001238X/xk5074Pb2SnO4-Pnam-P7sup10.hkl

Computing details top

Tin(IV) Dilead Oxide (Pb2SnO4-P42ombc-P0) top

Crystal data top

O₄Pb₂Sn	D_x = 8.268 Mg m⁻³
M_r = 597.11	Mo Kα radiation, λ = 0.71073 Å
Tetragonal, P4₂/mbc	Cell parameters from 349 reflections
a = 8.7276 (2) Å	θ = 4.7–29.1°
c = 6.2970 (2) Å	µ = 75.09 mm⁻¹
V = 479.65 (2) Å³	T = 298 K
Z = 4	Cuboid, colourless
F(000) = 984	0.08 × 0.04 × 0.03 mm

Data collection top

Xcalibur, Sapphire3 diffractometer	349 independent reflections
Radiation source: X-ray tube	304 reflections with I > 3σ(I)
Graphite monochromator	R_int = 0.042
Detector resolution: 15.9682 pixels mm^-1	θ_max = 29.1°, θ_min = 4.7°
ω scans	h = −11→11
Absorption correction: empirical (using intensity measurements) CrysAlisPro 1.171.39.46 (Rigaku Oxford Diffraction, 2018) Spherical absorption correction using equivalent radius and absorption coefficient. Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.	k = −11→11
T_min = 0.027, T_max = 0.05	l = −8→8
6359 measured reflections

Refinement top

Refinement on F	Primary atom site location: heavy-atom method
R[F² > 2σ(F²)] = 0.021	Secondary atom site location: difference Fourier map
wR(F²) = 0.025	Weighting scheme based on measured s.u.'s w = 1/(σ²(F) + 0.0001F²)
S = 1.26	(Δ/σ)_max = 0.003
349 reflections	Δρ_max = 0.38 e Å⁻³
22 parameters	Δρ_min = −0.40 e Å⁻³
0 restraints	Extinction correction: B-C type 1 Gaussian isotropic (Becker & Coppens, 1974)
0 constraints	Extinction coefficient: 42 (11)

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Pb1	0.85801 (5)	0.16055 (5)	0	0.02231 (16)
Sn1	0.5	0	0.25	0.0181 (2)
O1	0.6250 (8)	0.0973 (8)	0.5	0.020 (2)
O2	0.3344 (6)	0.1656 (6)	0.25	0.0251 (19)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Pb1	0.0225 (3)	0.0205 (3)	0.0239 (3)	0.00144 (15)	0	0
Sn1	0.0196 (3)	0.0196 (3)	0.0152 (5)	0.0015 (4)	0	0
O1	0.024 (4)	0.018 (4)	0.019 (4)	−0.003 (3)	0	0
O2	0.027 (3)	0.027 (3)	0.022 (4)	0.003 (3)	0.004 (2)	0.004 (2)

Geometric parameters (Å, º) top

Pb1—O1ⁱ	2.296 (7)	Sn1—O1^vi	2.095 (5)
Pb1—O2ⁱⁱ	2.196 (4)	Sn1—O1ⁱ	2.095 (5)
Pb1—O2ⁱⁱⁱ	2.196 (4)	Sn1—O1^vii	2.095 (5)
Sn1—Sn1^iv	3.1485 (2)	Sn1—O2	2.044 (5)
Sn1—Sn1^v	3.1485 (2)	Sn1—O2^vi	2.044 (5)
Sn1—O1	2.095 (5)

O1ⁱ—Pb1—O2ⁱⁱ	90.02 (18)	O1—Sn1—O2	94.7 (2)
O1ⁱ—Pb1—O2ⁱⁱⁱ	90.02 (18)	O1—Sn1—O2^vi	85.3 (2)
O2ⁱⁱ—Pb1—O2ⁱⁱⁱ	91.59 (14)	O1^vi—Sn1—O1ⁱ	170.6 (3)
Sn1^iv—Sn1—Sn1^v	180.0 (5)	O1^vi—Sn1—O1^vii	98.2 (2)
Sn1^iv—Sn1—O1	138.71 (14)	O1^vi—Sn1—O2	85.3 (2)
Sn1^iv—Sn1—O1^vi	138.71 (14)	O1^vi—Sn1—O2^vi	94.7 (2)
Sn1^iv—Sn1—O1ⁱ	41.29 (14)	O1ⁱ—Sn1—O1^vii	82.6 (2)
Sn1^iv—Sn1—O1^vii	41.29 (14)	O1ⁱ—Sn1—O2	85.3 (2)
Sn1^iv—Sn1—O2	90	O1ⁱ—Sn1—O2^vi	94.7 (2)
Sn1^iv—Sn1—O2^vi	90	O1^vii—Sn1—O2	94.7 (2)
Sn1^v—Sn1—O1	41.29 (14)	O1^vii—Sn1—O2^vi	85.3 (2)
Sn1^v—Sn1—O1^vi	41.29 (14)	O2—Sn1—O2^vi	180.0 (5)
Sn1^v—Sn1—O1ⁱ	138.71 (14)	Pb1ⁱ—O1—Sn1	118.2 (2)
Sn1^v—Sn1—O1^vii	138.71 (14)	Pb1ⁱ—O1—Sn1^v	118.2 (2)
Sn1^v—Sn1—O2	90	Sn1—O1—Sn1^v	97.4 (3)
Sn1^v—Sn1—O2^vi	90	Pb1^viii—O2—Pb1^ix	130.1 (2)
O1—Sn1—O1^vi	82.6 (2)	Pb1^viii—O2—Sn1	114.97 (18)
O1—Sn1—O1ⁱ	98.2 (2)	Pb1^ix—O2—Sn1	114.97 (18)
O1—Sn1—O1^vii	170.6 (3)

Symmetry codes: (i) y+1/2, x−1/2, −z+1/2; (ii) −y+1, x, z−1/2; (iii) −y+1, x, −z+1/2; (iv) −x+1, −y, −z; (v) −x+1, −y, −z+1; (vi) −x+1, −y, z; (vii) −y+1/2, −x+1/2, −z+1/2; (viii) y, −x+1, z+1/2; (ix) x−1/2, −y+1/2, −z.

Tin(IV) Dilead Oxide (Pb2SnO4-Pbam-P0) top

Crystal data top

O₄Pb₂Sn	D_x = 8.269 Mg m⁻³
M_r = 597.11	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, Pbam	Cell parameters from 679 reflections
a = 8.7288 (3) Å	θ = 4.6–29.1°
b = 8.7263 (3) Å	µ = 75.09 mm⁻¹
c = 6.2969 (2) Å	T = 298 K
V = 479.64 (3) Å³	Cuboid, colourless
Z = 4	0.08 × 0.04 × 0.03 mm
F(000) = 984

Data collection top

Xcalibur, Sapphire3 diffractometer	679 independent reflections
Radiation source: X-ray tube	540 reflections with I > 3σ(I)
Graphite monochromator	R_int = 0.041
Detector resolution: 15.9682 pixels mm^-1	θ_max = 29.1°, θ_min = 4.6°
ω scans	h = −11→11
Absorption correction: empirical (using intensity measurements) CrysAlisPro 1.171.39.46 (Rigaku Oxford Diffraction, 2018) Spherical absorption correction using equivalent radius and absorption coefficient. Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.	k = −11→11
T_min = 0.027, T_max = 0.05	l = −8→8
6760 measured reflections

Refinement top

Refinement on F	Primary atom site location: heavy-atom method
R[F² > 2σ(F²)] = 0.025	Secondary atom site location: difference Fourier map
wR(F²) = 0.028	Weighting scheme based on measured s.u.'s w = 1/(σ²(F) + 0.0001F²)
S = 1.20	(Δ/σ)_max = 0.006
679 reflections	Δρ_max = 0.49 e Å⁻³
40 parameters	Δρ_min = −0.42 e Å⁻³
0 restraints	Extinction correction: B-C type 1 Gaussian isotropic (Becker & Coppens, 1974)
0 constraints	Extinction coefficient: 39 (9)

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Pb1	0.35799 (6)	0.16055 (6)	0	0.02222 (17)
Pb2	0.16058 (5)	0.35808 (6)	−0.5	0.02232 (18)
Sn1	0.5	0.5	−0.24980 (16)	0.0181 (3)
O1	0.1264 (10)	0.0962 (11)	−0.5	0.021 (3)
O2	0.0979 (10)	0.1235 (10)	0	0.019 (3)
O3	0.3344 (7)	0.3344 (8)	−0.2479 (12)	0.025 (2)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Pb1	0.0226 (3)	0.0201 (3)	0.0239 (3)	0.00143 (19)	0	0
Pb2	0.0207 (3)	0.0225 (3)	0.0238 (3)	0.00141 (19)	0	0
Sn1	0.0196 (4)	0.0195 (5)	0.0152 (4)	−0.0015 (3)	0	0
O1	0.023 (5)	0.019 (5)	0.021 (5)	−0.002 (4)	0	0
O2	0.016 (4)	0.023 (5)	0.019 (5)	−0.002 (4)	0	0
O3	0.022 (4)	0.032 (4)	0.022 (4)	−0.003 (3)	−0.003 (3)	0.004 (3)

Geometric parameters (Å, º) top

Pb1—O2	2.293 (9)	Sn1—Sn1^iv	3.1459 (14)
Pb1—O3	2.186 (7)	Sn1—O1^v	2.099 (6)
Pb1—O3ⁱ	2.186 (7)	Sn1—O1^vi	2.099 (6)
Pb2—O1	2.305 (10)	Sn1—O2^vii	2.089 (6)
Pb2—O3	2.206 (7)	Sn1—O2^viii	2.089 (6)
Pb2—O3ⁱⁱ	2.206 (7)	Sn1—O3	2.044 (7)
Sn1—Sn1ⁱⁱⁱ	3.1510 (14)	Sn1—O3^ix	2.044 (7)

O2—Pb1—O3	90.3 (2)	O1^v—Sn1—O3	85.1 (3)
O2—Pb1—O3ⁱ	90.3 (2)	O1^v—Sn1—O3^ix	95.4 (3)
O3—Pb1—O3ⁱ	91.1 (3)	O1^vi—Sn1—O2^vii	170.6 (3)
O1—Pb2—O3	89.8 (2)	O1^vi—Sn1—O2^viii	98.3 (3)
O1—Pb2—O3ⁱⁱ	89.8 (2)	O1^vi—Sn1—O3	95.4 (3)
O3—Pb2—O3ⁱⁱ	92.1 (3)	O1^vi—Sn1—O3^ix	85.1 (3)
Sn1ⁱⁱⁱ—Sn1—Sn1^iv	180.0 (5)	O2^vii—Sn1—O2^viii	82.3 (3)
Sn1ⁱⁱⁱ—Sn1—O1^v	41.35 (19)	O2^vii—Sn1—O3	94.1 (3)
Sn1ⁱⁱⁱ—Sn1—O1^vi	41.35 (19)	O2^vii—Sn1—O3^ix	85.4 (3)
Sn1ⁱⁱⁱ—Sn1—O2^vii	138.83 (18)	O2^viii—Sn1—O3	85.4 (3)
Sn1ⁱⁱⁱ—Sn1—O2^viii	138.83 (18)	O2^viii—Sn1—O3^ix	94.1 (3)
Sn1ⁱⁱⁱ—Sn1—O3	90.3 (2)	O3—Sn1—O3^ix	179.3 (3)
Sn1ⁱⁱⁱ—Sn1—O3^ix	90.3 (2)	Pb2—O1—Sn1^x	117.7 (3)
Sn1^iv—Sn1—O1^v	138.65 (19)	Pb2—O1—Sn1^xi	117.7 (3)
Sn1^iv—Sn1—O1^vi	138.65 (19)	Sn1^x—O1—Sn1^xi	97.3 (4)
Sn1^iv—Sn1—O2^vii	41.17 (18)	Pb1—O2—Sn1^xii	118.5 (3)
Sn1^iv—Sn1—O2^viii	41.17 (18)	Pb1—O2—Sn1^xi	118.5 (3)
Sn1^iv—Sn1—O3	89.7 (2)	Sn1^xii—O2—Sn1^xi	97.7 (4)
Sn1^iv—Sn1—O3^ix	89.7 (2)	Pb1—O3—Pb2	130.1 (3)
O1^v—Sn1—O1^vi	82.7 (3)	Pb1—O3—Sn1	115.3 (3)
O1^v—Sn1—O2^vii	98.3 (3)	Pb2—O3—Sn1	114.6 (3)
O1^v—Sn1—O2^viii	170.6 (3)

Symmetry codes: (i) x, y, −z; (ii) x, y, −z−1; (iii) −x+1, −y+1, −z−1; (iv) −x+1, −y+1, −z; (v) −x+1/2, y+1/2, −z−1; (vi) x+1/2, −y+1/2, −z−1; (vii) −x+1/2, y+1/2, −z; (viii) x+1/2, −y+1/2, −z; (ix) −x+1, −y+1, z; (x) −x+1/2, y−1/2, −z−1; (xi) x−1/2, −y+1/2, z; (xii) −x+1/2, y−1/2, −z.

Tin(IV) Dilead Oxide (Pb2SnO4-Pbam-P1) top

Crystal data top

O₄Pb₂Sn	D_x = 8.63 Mg m⁻³
M_r = 597.11	Synchrotron radiation, λ = 0.28988 Å
Orthorhombic, Pbam	Cell parameters from 1011 reflections
a = 9.1901 (7) Å	θ = 1.9–17.9°
b = 7.9508 (3) Å	µ = 9.87 mm⁻¹
c = 6.2893 (7) Å	T = 293 K
V = 459.55 (6) Å³	Cuboid, colourless
Z = 4	0.08 × 0.04 × 0.03 mm
F(000) = 984

Data collection top

Esperanto-CrysAlisPro-abstract goniometer imported esperanto images diffractometer	1011 independent reflections
Radiation source: synchrotron	848 reflections with I > 3σ(I)
Synchrotron monochromator	R_int = 0.017
ω scans	θ_max = 17.9°, θ_min = 1.9°
Absorption correction: empirical (using intensity measurements) CrysAlisPro 1.171.39.46 (Rigaku Oxford Diffraction, 2018) Spherical absorption correction using equivalent radius and absorption coefficient. Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.	h = −16→15
T_min = 0.012, T_max = 0.02	k = −13→12
2491 measured reflections	l = −12→13

Refinement top

Refinement on F	Primary atom site location: heavy-atom method
R[F² > 2σ(F²)] = 0.023	Secondary atom site location: difference Fourier map
wR(F²) = 0.031	Weighting scheme based on measured s.u.'s w = 1/(σ²(F) + 0.0001F²)
S = 1.41	(Δ/σ)_max = 0.009
1011 reflections	Δρ_max = 1.46 e Å⁻³
40 parameters	Δρ_min = −0.92 e Å⁻³
0 restraints	Extinction correction: B-C type 1 Gaussian isotropic (Becker & Coppens, 1974)
0 constraints	Extinction coefficient: 610 (50)

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Pb1	0.33997 (3)	0.13860 (4)	0	0.01371 (9)
Pb2	0.17244 (3)	0.38926 (4)	−0.5	0.01373 (9)
Sn1	0.5	0.5	−0.24865 (6)	0.01054 (15)
O1	0.3868 (7)	0.6101 (8)	−0.5	0.0122 (18)
O2	0.6679 (5)	0.6684 (6)	−0.2496 (6)	0.0163 (13)
O3	0.4113 (6)	0.6399 (8)	0	0.0122 (18)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Pb1	0.01396 (16)	0.0134 (2)	0.01379 (10)	0.00039 (7)	0	0
Pb2	0.01124 (16)	0.0142 (2)	0.01579 (10)	0.00089 (6)	0	0
Sn1	0.0113 (3)	0.0125 (3)	0.00781 (13)	−0.00090 (11)	0	0
O1	0.023 (3)	0.005 (4)	0.0087 (14)	0.0038 (16)	0	0
O2	0.021 (2)	0.014 (3)	0.0141 (12)	−0.0052 (12)	0.0061 (14)	−0.0045 (16)
O3	0.021 (4)	0.008 (4)	0.0079 (14)	0.0019 (15)	0	0

Geometric parameters (Å, º) top

Pb1—O2ⁱ	2.196 (4)	Sn1—Sn1ⁱⁱ	3.1276 (9)
Pb1—O2ⁱⁱ	2.196 (4)	Sn1—O1	2.085 (4)
Pb1—O3ⁱⁱⁱ	2.309 (6)	Sn1—O1ⁱ	2.085 (4)
Pb2—Pb2^iv	3.6258 (6)	Sn1—O2	2.043 (5)
Pb2—O1^v	2.285 (6)	Sn1—O2ⁱ	2.043 (5)
Pb2—O2ⁱ	2.201 (4)	Sn1—O3	2.085 (4)
Pb2—O2^vi	2.201 (4)	Sn1—O3ⁱ	2.085 (4)
Sn1—Sn1^vi	3.1617 (9)

O2ⁱ—Pb1—O2ⁱⁱ	91.24 (16)	O1—Sn1—O2	95.7 (2)
O2ⁱ—Pb1—O3ⁱⁱⁱ	87.93 (16)	O1—Sn1—O2ⁱ	84.0 (2)
O2ⁱⁱ—Pb1—O3ⁱⁱⁱ	87.93 (16)	O1—Sn1—O3	98.60 (18)
Pb2^iv—Pb2—O1^v	105.27 (16)	O1—Sn1—O3ⁱ	171.0 (2)
Pb2^iv—Pb2—O2ⁱ	133.16 (11)	O1ⁱ—Sn1—O2	84.0 (2)
Pb2^iv—Pb2—O2^vi	133.16 (11)	O1ⁱ—Sn1—O2ⁱ	95.7 (2)
O1^v—Pb2—O2ⁱ	87.51 (17)	O1ⁱ—Sn1—O3	171.0 (2)
O1^v—Pb2—O2^vi	87.51 (17)	O1ⁱ—Sn1—O3ⁱ	98.60 (18)
O2ⁱ—Pb2—O2^vi	91.37 (16)	O2—Sn1—O2ⁱ	179.66 (15)
Sn1^vi—Sn1—Sn1ⁱⁱ	180.0 (5)	O2—Sn1—O3	87.0 (2)
Sn1^vi—Sn1—O1	40.70 (13)	O2—Sn1—O3ⁱ	93.2 (2)
Sn1^vi—Sn1—O1ⁱ	40.70 (13)	O2ⁱ—Sn1—O3	93.2 (2)
Sn1^vi—Sn1—O2	89.83 (11)	O2ⁱ—Sn1—O3ⁱ	87.0 (2)
Sn1^vi—Sn1—O2ⁱ	89.83 (11)	O3—Sn1—O3ⁱ	82.82 (18)
Sn1^vi—Sn1—O3	138.59 (13)	Pb2^vii—O1—Sn1	121.78 (19)
Sn1^vi—Sn1—O3ⁱ	138.59 (13)	Pb2^vii—O1—Sn1^vi	121.78 (19)
Sn1ⁱⁱ—Sn1—O1	139.30 (13)	Sn1—O1—Sn1^vi	98.6 (3)
Sn1ⁱⁱ—Sn1—O1ⁱ	139.30 (13)	Pb1ⁱ—O2—Pb2ⁱ	132.8 (2)
Sn1ⁱⁱ—Sn1—O2	90.17 (11)	Pb1ⁱ—O2—Sn1	115.52 (19)
Sn1ⁱⁱ—Sn1—O2ⁱ	90.17 (11)	Pb2ⁱ—O2—Sn1	111.7 (2)
Sn1ⁱⁱ—Sn1—O3	41.41 (13)	Pb1^viii—O3—Sn1	112.87 (19)
Sn1ⁱⁱ—Sn1—O3ⁱ	41.41 (13)	Pb1^viii—O3—Sn1ⁱⁱ	112.87 (19)
O1—Sn1—O1ⁱ	81.41 (19)	Sn1—O3—Sn1ⁱⁱ	97.2 (3)

Symmetry codes: (i) −x+1, −y+1, z; (ii) −x+1, −y+1, −z; (iii) −x+1/2, y−1/2, −z; (iv) −x, −y+1, z; (v) −x+1/2, y−1/2, −z−1; (vi) −x+1, −y+1, −z−1; (vii) −x+1/2, y+1/2, −z−1; (viii) −x+1/2, y+1/2, −z.

Tin(IV) Dilead Oxide (Pb2SnO4-Pbam-P2) top

Crystal data top

O₄Pb₂Sn	D_x = 9.271 Mg m⁻³
M_r = 597.11	Synchrotron radiation, λ = 0.28988 Å
Orthorhombic, Pbam	Cell parameters from 898 reflections
a = 9.3799 (7) Å	θ = 2.0–17.8°
b = 7.2103 (3) Å	µ = 10.60 mm⁻¹
c = 6.3250 (7) Å	T = 293 K
V = 427.77 (6) Å³	Cuboid, orange
Z = 4	0.08 × 0.04 × 0.03 mm
F(000) = 984

Data collection top

Esperanto-CrysAlisPro-abstract goniometer imported esperanto images diffractometer	898 independent reflections
Radiation source: synchrotron	824 reflections with I > 3σ(I)
Synchrotron monochromator	R_int = 0.015
ω scans	θ_max = 17.8°, θ_min = 2.0°
Absorption correction: empirical (using intensity measurements) CrysAlisPro 1.171.39.46 (Rigaku Oxford Diffraction, 2018) Spherical absorption correction using equivalent radius and absorption coefficient. Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.	h = −16→17
T_min = 0.009, T_max = 0.017	k = −11→10
2276 measured reflections	l = −13→12

Refinement top

Refinement on F	Primary atom site location: heavy-atom method
R[F² > 2σ(F²)] = 0.021	Secondary atom site location: difference Fourier map
wR(F²) = 0.029	Weighting scheme based on measured s.u.'s w = 1/(σ²(F) + 0.0001F²)
S = 1.60	(Δ/σ)_max = 0.008
898 reflections	Δρ_max = 1.14 e Å⁻³
40 parameters	Δρ_min = −1.44 e Å⁻³
0 restraints	Extinction correction: B-C type 1 Gaussian isotropic (Becker & Coppens, 1974)
0 constraints	Extinction coefficient: 890 (50)

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Pb1	0.32870 (3)	0.11814 (5)	0	0.01235 (9)
Pb2	0.17591 (3)	0.43375 (5)	−0.5	0.01221 (9)
Sn1	0.5	0.5	−0.24846 (5)	0.00974 (13)
O1	0.4030 (6)	0.6348 (9)	−0.5	0.0117 (16)
O2	0.6766 (4)	0.6632 (7)	−0.2490 (6)	0.0156 (13)
O3	0.4181 (5)	0.6571 (8)	0	0.0103 (16)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Pb1	0.01252 (14)	0.0126 (2)	0.01198 (9)	0.00008 (6)	0	0
Pb2	0.01056 (14)	0.0129 (2)	0.01322 (9)	0.00035 (6)	0	0
Sn1	0.0102 (2)	0.0113 (3)	0.00773 (12)	−0.00080 (10)	0	0
O1	0.012 (3)	0.014 (4)	0.0091 (12)	0.0032 (13)	0	0
O2	0.019 (2)	0.015 (3)	0.0127 (10)	−0.0040 (11)	0.0029 (12)	−0.0043 (15)
O3	0.013 (3)	0.010 (4)	0.0081 (11)	−0.0005 (13)	0	0

Geometric parameters (Å, º) top

Pb1—Pb1ⁱ	3.6372 (6)	Pb2—O2^iv	2.218 (4)
Pb1—Pb2ⁱⁱ	3.4309 (7)	Pb2—O2^vii	2.218 (4)
Pb1—Pb2ⁱⁱⁱ	3.4309 (7)	Sn1—Sn1^vii	3.1822 (8)
Pb1—O2^iv	2.230 (4)	Sn1—Sn1^v	3.1428 (8)
Pb1—O2^v	2.230 (4)	Sn1—O1	2.077 (4)
Pb1—O3ⁱⁱⁱ	2.334 (5)	Sn1—O1^iv	2.077 (4)
Pb2—Pb2^vi	3.4353 (6)	Sn1—O2	2.032 (4)
Pb2—Sn1	3.4644 (5)	Sn1—O2^iv	2.032 (4)
Pb2—Sn1^vii	3.4644 (5)	Sn1—O3	2.083 (4)
Pb2—O1ⁱⁱ	2.276 (6)	Sn1—O3^iv	2.083 (4)

Pb1ⁱ—Pb1—Pb2ⁱⁱ	80.188 (7)	Pb2—Sn1—O2^iv	37.23 (11)
Pb1ⁱ—Pb1—Pb2ⁱⁱⁱ	80.188 (7)	Pb2—Sn1—O3	95.66 (13)
Pb1ⁱ—Pb1—O2^iv	110.58 (10)	Pb2—Sn1—O3^iv	126.46 (15)
Pb1ⁱ—Pb1—O2^v	110.58 (10)	Pb2^iv—Sn1—Sn1^vii	62.660 (6)
Pb1ⁱ—Pb1—O3ⁱⁱⁱ	158.98 (14)	Pb2^iv—Sn1—Sn1^v	117.340 (6)
Pb2ⁱⁱ—Pb1—Pb2ⁱⁱⁱ	134.374 (13)	Pb2^iv—Sn1—O1	88.18 (13)
Pb2ⁱⁱ—Pb1—O2^iv	67.87 (11)	Pb2^iv—Sn1—O1^iv	47.78 (15)
Pb2ⁱⁱ—Pb1—O2^v	157.64 (11)	Pb2^iv—Sn1—O2	37.23 (11)
Pb2ⁱⁱ—Pb1—O3ⁱⁱⁱ	91.96 (6)	Pb2^iv—Sn1—O2^iv	142.66 (11)
Pb2ⁱⁱⁱ—Pb1—O2^iv	157.64 (11)	Pb2^iv—Sn1—O3	126.46 (15)
Pb2ⁱⁱⁱ—Pb1—O2^v	67.87 (11)	Pb2^iv—Sn1—O3^iv	95.66 (13)
Pb2ⁱⁱⁱ—Pb1—O3ⁱⁱⁱ	91.96 (6)	Sn1^vii—Sn1—Sn1^v	180.0 (5)
O2^iv—Pb1—O2^v	89.82 (15)	Sn1^vii—Sn1—O1	39.98 (12)
O2^iv—Pb1—O3ⁱⁱⁱ	83.82 (15)	Sn1^vii—Sn1—O1^iv	39.98 (12)
O2^v—Pb1—O3ⁱⁱⁱ	83.82 (15)	Sn1^vii—Sn1—O2	89.92 (10)
Pb1^viii—Pb2—Pb1^ix	134.374 (13)	Sn1^vii—Sn1—O2^iv	89.92 (10)
Pb1^viii—Pb2—Pb2^vi	83.117 (7)	Sn1^vii—Sn1—O3	138.97 (12)
Pb1^viii—Pb2—Sn1	112.389 (9)	Sn1^vii—Sn1—O3^iv	138.97 (12)
Pb1^viii—Pb2—Sn1^vii	62.239 (7)	Sn1^v—Sn1—O1	140.02 (12)
Pb1^viii—Pb2—O1ⁱⁱ	111.25 (2)	Sn1^v—Sn1—O1^iv	140.02 (12)
Pb1^viii—Pb2—O2^iv	142.15 (10)	Sn1^v—Sn1—O2	90.08 (10)
Pb1^viii—Pb2—O2^vii	57.97 (11)	Sn1^v—Sn1—O2^iv	90.08 (10)
Pb1^ix—Pb2—Pb2^vi	83.117 (7)	Sn1^v—Sn1—O3	41.03 (12)
Pb1^ix—Pb2—Sn1	62.239 (7)	Sn1^v—Sn1—O3^iv	41.03 (12)
Pb1^ix—Pb2—Sn1^vii	112.389 (9)	O1—Sn1—O1^iv	79.97 (17)
Pb1^ix—Pb2—O1ⁱⁱ	111.25 (2)	O1—Sn1—O2	94.88 (19)
Pb1^ix—Pb2—O2^iv	57.97 (11)	O1—Sn1—O2^iv	85.00 (19)
Pb1^ix—Pb2—O2^vii	142.15 (10)	O1—Sn1—O3	99.29 (17)
Pb2^vi—Pb2—Sn1	143.563 (9)	O1—Sn1—O3^iv	174.1 (2)
Pb2^vi—Pb2—Sn1^vii	143.563 (9)	O1^iv—Sn1—O2	85.00 (19)
Pb2^vi—Pb2—O1ⁱⁱ	87.20 (13)	O1^iv—Sn1—O2^iv	94.88 (19)
Pb2^vi—Pb2—O2^iv	133.32 (10)	O1^iv—Sn1—O3	174.1 (2)
Pb2^vi—Pb2—O2^vii	133.32 (10)	O1^iv—Sn1—O3^iv	99.29 (17)
Sn1—Pb2—Sn1^vii	54.679 (10)	O2—Sn1—O2^iv	179.85 (14)
Sn1—Pb2—O1ⁱⁱ	114.55 (11)	O2—Sn1—O3	89.24 (18)
Sn1—Pb2—O2^iv	33.65 (11)	O2—Sn1—O3^iv	90.88 (18)
Sn1—Pb2—O2^vii	79.94 (10)	O2^iv—Sn1—O3	90.88 (18)
Sn1^vii—Pb2—O1ⁱⁱ	114.55 (11)	O2^iv—Sn1—O3^iv	89.24 (18)
Sn1^vii—Pb2—O2^iv	79.94 (10)	O3—Sn1—O3^iv	82.06 (16)
Sn1^vii—Pb2—O2^vii	33.65 (11)	Pb2^viii—O1—Sn1	125.92 (16)
O1ⁱⁱ—Pb2—O2^iv	84.55 (15)	Pb2^viii—O1—Sn1^vii	125.92 (16)
O1ⁱⁱ—Pb2—O2^vii	84.55 (15)	Sn1—O1—Sn1^vii	100.0 (2)
O2^iv—Pb2—O2^vii	91.45 (14)	Pb1^iv—O2—Pb2^iv	137.9 (2)
Pb2—Sn1—Pb2^iv	125.321 (11)	Pb1^iv—O2—Sn1	112.95 (17)
Pb2—Sn1—Sn1^vii	62.660 (6)	Pb2^iv—O2—Sn1	109.12 (19)
Pb2—Sn1—Sn1^v	117.340 (6)	Pb1^ix—O3—Sn1	107.45 (18)
Pb2—Sn1—O1	47.78 (15)	Pb1^ix—O3—Sn1^v	107.45 (18)
Pb2—Sn1—O1^iv	88.18 (13)	Sn1—O3—Sn1^v	97.9 (2)
Pb2—Sn1—O2	142.66 (11)

Symmetry codes: (i) −x+1, −y, z; (ii) −x+1/2, y−1/2, −z−1; (iii) −x+1/2, y−1/2, −z; (iv) −x+1, −y+1, z; (v) −x+1, −y+1, −z; (vi) −x, −y+1, z; (vii) −x+1, −y+1, −z−1; (viii) −x+1/2, y+1/2, −z−1; (ix) −x+1/2, y+1/2, −z.

Tin(IV) Dilead Oxide (Pb2SnO4-Pbam-P3) top

Crystal data top

O₄Pb₂Sn	D_x = 9.708 Mg m⁻³
M_r = 597.11	Synchrotron radiation, λ = 0.28988 Å
Orthorhombic, Pbam	Cell parameters from 1085 reflections
a = 9.3641 (6) Å	θ = 2.0–18.0°
b = 6.8646 (6) Å	µ = 11.1 mm⁻¹
c = 6.3553 (2) Å	T = 293 K
V = 408.52 (5) Å³	Cuboid, red
Z = 4	0.08 × 0.04 × 0.03 mm
F(000) = 984

Data collection top

Esperanto-CrysAlisPro-abstract goniometer imported esperanto images diffractometer	1085 independent reflections
Radiation source: synchrotron	966 reflections with I > 3σ(I)
Synchrotron monochromator	R_int = 0.037
ω scans	θ_max = 18.0°, θ_min = 2.0°
Absorption correction: empirical (using intensity measurements) CrysAlisPro 1.171.39.46 (Rigaku Oxford Diffraction, 2018) Spherical absorption correction using equivalent radius and absorption coefficient. Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.	h = −17→18
T_min = 0.008, T_max = 0.016	k = −9→12
2571 measured reflections	l = −12→13

Refinement top

Refinement on F	Primary atom site location: heavy-atom method
R[F² > 2σ(F²)] = 0.087	Secondary atom site location: difference Fourier map
wR(F²) = 0.143	Weighting scheme based on measured s.u.'s w = 1/(σ²(F) + 0.0001F²)
S = 5.06	(Δ/σ)_max = 0.014
1085 reflections	Δρ_max = 3.22 e Å⁻³
29 parameters	Δρ_min = −2.85 e Å⁻³
0 restraints	Extinction correction: B-C type 1 Gaussian isotropic (Becker & Coppens, 1974)
0 constraints	Extinction coefficient: 580 (50)

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Pb1	0.32668 (15)	0.1042 (3)	0	0.0128 (4)
Pb2	0.17615 (14)	0.4628 (3)	−0.5	0.0120 (4)
Sn1	0.5	0.5	−0.2439 (3)	0.0100 (7)
O1	0.403 (2)	0.635 (4)	−0.5	0.004 (3)*
O2	0.682 (3)	0.660 (5)	−0.255 (3)	0.021 (4)*
O3	0.417 (3)	0.660 (6)	0	0.015 (5)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Pb1	0.0122 (6)	0.0142 (10)	0.0121 (4)	0.0002 (3)	0	0
Pb2	0.0114 (6)	0.0110 (9)	0.0135 (5)	0.0002 (3)	0	0
Sn1	0.0101 (10)	0.0141 (16)	0.0057 (6)	−0.0014 (6)	0	0

Geometric parameters (Å, º) top

Pb1—Pb1ⁱ	3.547 (2)	Pb2—O2^iv	2.21 (3)
Pb1—Pb2ⁱⁱ	3.3227 (9)	Pb2—O2^vii	2.21 (3)
Pb1—Pb2ⁱⁱⁱ	3.3227 (9)	Sn1—Sn1^vii	3.255 (3)
Pb1—O2^iv	2.29 (3)	Sn1—Sn1^v	3.100 (3)
Pb1—O2^v	2.29 (3)	Sn1—O1	2.082 (15)
Pb1—O3ⁱⁱⁱ	2.31 (3)	Sn1—O1^iv	2.082 (15)
Pb2—Pb2^vi	3.3384 (19)	Sn1—O2	2.03 (3)
Pb2—Sn1	3.4513 (15)	Sn1—O2^iv	2.03 (3)
Pb2—Sn1^vii	3.4513 (15)	Sn1—O3	2.05 (2)
Pb2—O1	2.43 (2)	Sn1—O3^iv	2.05 (2)
Pb2—O1ⁱⁱ	2.37 (3)

Pb1ⁱ—Pb1—Pb2ⁱⁱ	83.66 (4)	Pb2—Sn1—O1	44.0 (6)
Pb1ⁱ—Pb1—Pb2ⁱⁱⁱ	83.66 (4)	Pb2—Sn1—O1^iv	89.0 (5)
Pb1ⁱ—Pb1—O2^iv	108.5 (7)	Pb2—Sn1—O2	139.6 (7)
Pb1ⁱ—Pb1—O2^v	108.5 (7)	Pb2—Sn1—O2^iv	37.4 (7)
Pb1ⁱ—Pb1—O3ⁱⁱⁱ	165.7 (10)	Pb2—Sn1—O3	93.6 (7)
Pb2ⁱⁱ—Pb1—Pb2ⁱⁱⁱ	146.02 (8)	Pb2—Sn1—O3^iv	130.5 (9)
Pb2ⁱⁱ—Pb1—O2^iv	62.0 (7)	Pb2^iv—Sn1—Sn1^vii	61.86 (3)
Pb2ⁱⁱ—Pb1—O2^v	151.9 (7)	Pb2^iv—Sn1—Sn1^v	118.14 (3)
Pb2ⁱⁱ—Pb1—O3ⁱⁱⁱ	92.3 (3)	Pb2^iv—Sn1—O1	89.0 (5)
Pb2ⁱⁱⁱ—Pb1—O2^iv	151.9 (7)	Pb2^iv—Sn1—O1^iv	44.0 (6)
Pb2ⁱⁱⁱ—Pb1—O2^v	62.0 (7)	Pb2^iv—Sn1—O2	37.4 (7)
Pb2ⁱⁱⁱ—Pb1—O3ⁱⁱⁱ	92.3 (3)	Pb2^iv—Sn1—O2^iv	139.6 (7)
O2^iv—Pb1—O2^v	90.0 (10)	Pb2^iv—Sn1—O3	130.5 (9)
O2^iv—Pb1—O3ⁱⁱⁱ	81.3 (10)	Pb2^iv—Sn1—O3^iv	93.6 (7)
O2^v—Pb1—O3ⁱⁱⁱ	81.3 (10)	Sn1^vii—Sn1—Sn1^v	180.0 (5)
Pb1^viii—Pb2—Pb1^ix	146.02 (8)	Sn1^vii—Sn1—O1	38.6 (5)
Pb1^viii—Pb2—Pb2^vi	86.99 (4)	Sn1^vii—Sn1—O1^iv	38.6 (5)
Pb1^viii—Pb2—Sn1	115.87 (5)	Sn1^vii—Sn1—O2	88.0 (5)
Pb1^viii—Pb2—Sn1^vii	62.25 (4)	Sn1^vii—Sn1—O2^iv	88.0 (5)
Pb1^viii—Pb2—O1	82.24 (16)	Sn1^vii—Sn1—O3	139.0 (8)
Pb1^viii—Pb2—O1ⁱⁱ	105.96 (7)	Sn1^vii—Sn1—O3^iv	139.0 (8)
Pb1^viii—Pb2—O2^iv	142.1 (6)	Sn1^v—Sn1—O1	141.4 (5)
Pb1^viii—Pb2—O2^vii	56.2 (7)	Sn1^v—Sn1—O1^iv	141.4 (5)
Pb1^ix—Pb2—Pb2^vi	86.99 (4)	Sn1^v—Sn1—O2	92.0 (5)
Pb1^ix—Pb2—Sn1	62.25 (4)	Sn1^v—Sn1—O2^iv	92.0 (5)
Pb1^ix—Pb2—Sn1^vii	115.87 (5)	Sn1^v—Sn1—O3	41.0 (8)
Pb1^ix—Pb2—O1	82.24 (16)	Sn1^v—Sn1—O3^iv	41.0 (8)
Pb1^ix—Pb2—O1ⁱⁱ	105.96 (7)	O1—Sn1—O1^iv	77.1 (7)
Pb1^ix—Pb2—O2^iv	56.2 (7)	O1—Sn1—O2	95.6 (9)
Pb1^ix—Pb2—O2^vii	142.1 (6)	O1—Sn1—O2^iv	81.2 (9)
Pb2^vi—Pb2—Sn1	148.99 (4)	O1—Sn1—O3	100.8 (9)
Pb2^vi—Pb2—Sn1^vii	148.99 (4)	O1—Sn1—O3^iv	173.7 (12)
Pb2^vi—Pb2—O1	142.1 (6)	O1^iv—Sn1—O2	81.2 (9)
Pb2^vi—Pb2—O1ⁱⁱ	80.6 (5)	O1^iv—Sn1—O2^iv	95.6 (9)
Pb2^vi—Pb2—O2^iv	130.6 (7)	O1^iv—Sn1—O3	173.7 (12)
Pb2^vi—Pb2—O2^vii	130.6 (7)	O1^iv—Sn1—O3^iv	100.8 (9)
Sn1—Pb2—Sn1^vii	56.28 (4)	O2—Sn1—O2^iv	176.0 (8)
Sn1—Pb2—O1	36.5 (4)	O2—Sn1—O3	93.1 (12)
Sn1—Pb2—O1ⁱⁱ	110.2 (4)	O2—Sn1—O3^iv	89.9 (12)
Sn1—Pb2—O2^iv	33.8 (8)	O2^iv—Sn1—O3	89.9 (12)
Sn1—Pb2—O2^vii	80.4 (7)	O2^iv—Sn1—O3^iv	93.1 (12)
Sn1^vii—Pb2—O1	36.5 (4)	O3—Sn1—O3^iv	81.9 (11)
Sn1^vii—Pb2—O1ⁱⁱ	110.2 (4)	Pb2—O1—Pb2^viii	100.9 (7)
Sn1^vii—Pb2—O2^iv	80.4 (7)	Pb2—O1—Sn1	99.5 (8)
Sn1^vii—Pb2—O2^vii	33.8 (8)	Pb2—O1—Sn1^vii	99.5 (8)
O1—Pb2—O1ⁱⁱ	137.3 (8)	Pb2^viii—O1—Sn1	124.0 (7)
O1—Pb2—O2^iv	70.2 (9)	Pb2^viii—O1—Sn1^vii	124.0 (7)
O1—Pb2—O2^vii	70.2 (9)	Sn1—O1—Sn1^vii	102.9 (10)
O1ⁱⁱ—Pb2—O2^iv	80.0 (9)	Pb1^iv—O2—Pb2^iv	142.0 (14)
O1ⁱⁱ—Pb2—O2^vii	80.0 (9)	Pb1^iv—O2—Sn1	109.1 (11)
O2^iv—Pb2—O2^vii	89.4 (9)	Pb2^iv—O2—Sn1	108.8 (13)
Pb2—Sn1—Pb2^iv	123.72 (6)	Pb1^ix—O3—Sn1	106.6 (12)
Pb2—Sn1—Sn1^vii	61.86 (3)	Pb1^ix—O3—Sn1^v	106.6 (12)
Pb2—Sn1—Sn1^v	118.14 (3)	Sn1—O3—Sn1^v	98.1 (16)

Tin(IV) Dilead Oxide (Pb2SnO4-Pbam-P4) top

Crystal data top

O₄Pb₂Sn	D_x = 10.056 Mg m⁻³
M_r = 597.11	Synchrotron radiation, λ = 0.28988 Å
Orthorhombic, Pbam	Cell parameters from 1004 reflections
a = 9.3169 (6) Å	θ = 2.0–18°
b = 6.6337 (6) Å	µ = 11.50 mm⁻¹
c = 6.3808 (2) Å	T = 293 K
V = 394.37 (5) Å³	Cuboid, colourless
Z = 4	0.08 × 0.04 × 0.03 mm
F(000) = 984

Data collection top

Esperanto-CrysAlisPro-abstract goniometer imported esperanto images diffractometer	1004 independent reflections
Radiation source: synchrotron	882 reflections with I > 3σ(I)
Synchrotron monochromator	R_int = 0.074
ω scans	θ_max = 18°, θ_min = 2.0°
Absorption correction: empirical (using intensity measurements) CrysAlisPro 1.171.39.46 (Rigaku Oxford Diffraction, 2018) Spherical absorption correction using equivalent radius and absorption coefficient. Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.	h = −16→19
T_min = 0.007, T_max = 0.015	k = −11→8
2357 measured reflections	l = −13→13

Refinement top

Refinement on F	Primary atom site location: heavy-atom method
R[F² > 2σ(F²)] = 0.139	Secondary atom site location: difference Fourier map
wR(F²) = 0.188	Weighting scheme based on measured s.u.'s w = 1/(σ²(F) + 0.0001F²)
S = 5.97	(Δ/σ)_max = 0.011
1004 reflections	Δρ_max = 5.62 e Å⁻³
26 parameters	Δρ_min = −5.95 e Å⁻³
0 restraints	Extinction correction: B-C type 1 Gaussian isotropic (Becker & Coppens, 1974)
0 constraints	Extinction coefficient: 260 (150)

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Pb1	0.3249 (2)	0.0880 (4)	0	0.0118 (6)
Pb2	0.1744 (2)	0.4897 (4)	−0.5	0.0134 (6)
Sn1	0.5	0.5	−0.2414 (4)	0.0077 (5)*
O1	0.410 (4)	0.661 (8)	−0.5	0.013 (6)*
O2	0.688 (4)	0.651 (8)	−0.256 (5)	0.024 (7)*
O3	0.419 (9)	0.691 (16)	0	0.048 (18)*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Pb1	0.0119 (9)	0.0113 (15)	0.0121 (6)	−0.0005 (5)	0	0
Pb2	0.0101 (9)	0.0147 (15)	0.0155 (7)	0.0009 (5)	0	0

Geometric parameters (Å, º) top

Pb1—Pb1ⁱ	3.466 (3)	Pb2—Pb2^iv	3.603 (4)
Pb1—Pb1ⁱⁱ	3.598 (4)	Pb2—Pb2^ix	3.603 (4)
Pb1—Pb1ⁱⁱⁱ	3.598 (4)	Pb2—Sn1	3.454 (2)
Pb1—Pb2^iv	3.2564 (8)	Pb2—Sn1^x	3.454 (2)
Pb1—Pb2ⁱⁱ	3.2564 (8)	Pb2—O1^iv	2.32 (5)
Pb1—Sn1ⁱⁱ	3.446 (2)	Pb2—O2^vi	2.22 (4)
Pb1—Sn1^v	3.446 (2)	Pb2—O2^x	2.22 (4)
Pb1—O2^vi	2.38 (4)	Sn1—Sn1^x	3.300 (4)
Pb1—O2^vii	2.38 (4)	Sn1—Sn1^vii	3.081 (4)
Pb1—O3ⁱⁱ	2.37 (9)	Sn1—O2	2.02 (4)
Pb2—Pb2^viii	3.253 (3)	Sn1—O2^vi	2.02 (4)

Pb1ⁱ—Pb1—Pb1ⁱⁱ	93.14 (8)	Pb1ⁱⁱⁱ—Pb2—O2^x	140.3 (9)
Pb1ⁱ—Pb1—Pb1ⁱⁱⁱ	132.51 (9)	Pb2^viii—Pb2—Pb2^iv	115.42 (9)
Pb1ⁱ—Pb1—Pb2^iv	86.02 (5)	Pb2^viii—Pb2—Pb2^ix	110.61 (9)
Pb1ⁱ—Pb1—Pb2ⁱⁱ	86.02 (5)	Pb2^viii—Pb2—Sn1	151.25 (4)
Pb1ⁱ—Pb1—Sn1ⁱⁱ	140.35 (7)	Pb2^viii—Pb2—Sn1^x	151.25 (4)
Pb1ⁱ—Pb1—Sn1^v	140.35 (7)	Pb2^viii—Pb2—O1^iv	72.6 (10)
Pb1ⁱ—Pb1—O2^vi	107.0 (9)	Pb2^viii—Pb2—O2^vi	126.4 (10)
Pb1ⁱ—Pb1—O2^vii	107.0 (9)	Pb2^viii—Pb2—O2^x	126.4 (10)
Pb1ⁱ—Pb1—O3ⁱⁱ	177 (3)	Pb2^iv—Pb2—Pb2^ix	133.97 (7)
Pb1ⁱⁱ—Pb1—Pb1ⁱⁱⁱ	134.35 (7)	Pb2^iv—Pb2—Sn1	71.02 (5)
Pb1ⁱⁱ—Pb1—Pb2^iv	79.41 (6)	Pb2^iv—Pb2—Sn1^x	71.02 (5)
Pb1ⁱⁱ—Pb1—Pb2ⁱⁱ	79.41 (6)	Pb2^iv—Pb2—O1^iv	42.8 (10)
Pb1ⁱⁱ—Pb1—Sn1ⁱⁱ	60.21 (5)	Pb2^iv—Pb2—O2^vi	52.3 (12)
Pb1ⁱⁱ—Pb1—Sn1^v	60.21 (5)	Pb2^iv—Pb2—O2^x	52.3 (12)
Pb1ⁱⁱ—Pb1—O2^vi	130.5 (10)	Pb2^ix—Pb2—Sn1	68.80 (5)
Pb1ⁱⁱ—Pb1—O2^vii	130.5 (10)	Pb2^ix—Pb2—Sn1^x	68.80 (5)
Pb1ⁱⁱ—Pb1—O3ⁱⁱ	84 (3)	Pb2^ix—Pb2—O1^iv	176.8 (10)
Pb1ⁱⁱⁱ—Pb1—Pb2^iv	100.68 (6)	Pb2^ix—Pb2—O2^vi	99.3 (13)
Pb1ⁱⁱⁱ—Pb1—Pb2ⁱⁱ	100.68 (6)	Pb2^ix—Pb2—O2^x	99.3 (13)
Pb1ⁱⁱⁱ—Pb1—Sn1ⁱⁱ	79.36 (5)	Sn1—Pb2—Sn1^x	57.07 (6)
Pb1ⁱⁱⁱ—Pb1—Sn1^v	79.36 (5)	Sn1—Pb2—O1^iv	108.5 (8)
Pb1ⁱⁱⁱ—Pb1—O2^vi	46.4 (10)	Sn1—Pb2—O2^vi	33.6 (12)
Pb1ⁱⁱⁱ—Pb1—O2^vii	46.4 (10)	Sn1—Pb2—O2^x	80.6 (9)
Pb1ⁱⁱⁱ—Pb1—O3ⁱⁱ	50 (3)	Sn1^x—Pb2—O1^iv	108.5 (8)
Pb2^iv—Pb1—Pb2ⁱⁱ	156.90 (11)	Sn1^x—Pb2—O2^vi	80.6 (9)
Pb2^iv—Pb1—Sn1ⁱⁱ	113.94 (7)	Sn1^x—Pb2—O2^x	33.6 (12)
Pb2^iv—Pb1—Sn1^v	61.96 (5)	O1^iv—Pb2—O2^vi	78.5 (15)
Pb2^iv—Pb1—O2^vi	58.3 (10)	O1^iv—Pb2—O2^x	78.5 (15)
Pb2^iv—Pb1—O2^vii	144.8 (10)	O2^vi—Pb2—O2^x	88.9 (14)
Pb2^iv—Pb1—O3ⁱⁱ	93.4 (5)	Pb1ⁱⁱⁱ—Sn1—Pb1^xi	126.90 (8)
Pb2ⁱⁱ—Pb1—Sn1ⁱⁱ	61.96 (5)	Pb1ⁱⁱⁱ—Sn1—Pb2	56.32 (2)
Pb2ⁱⁱ—Pb1—Sn1^v	113.94 (7)	Pb1ⁱⁱⁱ—Sn1—Pb2^vi	169.00 (6)
Pb2ⁱⁱ—Pb1—O2^vi	144.8 (10)	Pb1ⁱⁱⁱ—Sn1—Sn1^x	116.55 (4)
Pb2ⁱⁱ—Pb1—O2^vii	58.3 (10)	Pb1ⁱⁱⁱ—Sn1—Sn1^vii	63.45 (4)
Pb2ⁱⁱ—Pb1—O3ⁱⁱ	93.4 (5)	Pb1ⁱⁱⁱ—Sn1—O2	134.3 (13)
Sn1ⁱⁱ—Pb1—Sn1^v	53.10 (6)	Pb1ⁱⁱⁱ—Sn1—O2^vi	48.9 (12)
Sn1ⁱⁱ—Pb1—O2^vi	112.6 (9)	Pb1^xi—Sn1—Pb2	169.00 (6)
Sn1ⁱⁱ—Pb1—O2^vii	76.8 (9)	Pb1^xi—Sn1—Pb2^vi	56.32 (2)
Sn1ⁱⁱ—Pb1—O3ⁱⁱ	37.6 (17)	Pb1^xi—Sn1—Sn1^x	116.55 (4)
Sn1^v—Pb1—O2^vi	76.8 (9)	Pb1^xi—Sn1—Sn1^vii	63.45 (4)
Sn1^v—Pb1—O2^vii	112.6 (9)	Pb1^xi—Sn1—O2	48.9 (12)
Sn1^v—Pb1—O3ⁱⁱ	37.6 (17)	Pb1^xi—Sn1—O2^vi	134.3 (13)
O2^vi—Pb1—O2^vii	86.5 (15)	Pb2—Sn1—Pb2^vi	122.93 (8)
O2^vi—Pb1—O3ⁱⁱ	75 (2)	Pb2—Sn1—Sn1^x	61.46 (4)
O2^vii—Pb1—O3ⁱⁱ	75 (2)	Pb2—Sn1—Sn1^vii	118.54 (4)
Pb1^ix—Pb2—Pb1ⁱⁱⁱ	156.90 (11)	Pb2—Sn1—O2	138.5 (11)
Pb1^ix—Pb2—Pb2^viii	89.63 (5)	Pb2—Sn1—O2^vi	37.5 (12)
Pb1^ix—Pb2—Pb2^iv	100.57 (6)	Pb2^vi—Sn1—Sn1^x	61.46 (4)
Pb1^ix—Pb2—Pb2^ix	79.33 (6)	Pb2^vi—Sn1—Sn1^vii	118.54 (4)
Pb1^ix—Pb2—Sn1	117.54 (7)	Pb2^vi—Sn1—O2	37.5 (12)
Pb1^ix—Pb2—Sn1^x	61.72 (5)	Pb2^vi—Sn1—O2^vi	138.5 (11)
Pb1^ix—Pb2—O1^iv	100.90 (9)	Sn1^x—Sn1—Sn1^vii	180.0 (5)
Pb1^ix—Pb2—O2^vi	140.3 (9)	Sn1^x—Sn1—O2	87.4 (9)
Pb1^ix—Pb2—O2^x	52.9 (11)	Sn1^x—Sn1—O2^vi	87.4 (9)
Pb1ⁱⁱⁱ—Pb2—Pb2^viii	89.63 (5)	Sn1^vii—Sn1—O2	92.6 (9)
Pb1ⁱⁱⁱ—Pb2—Pb2^iv	100.57 (6)	Sn1^vii—Sn1—O2^vi	92.6 (9)
Pb1ⁱⁱⁱ—Pb2—Pb2^ix	79.33 (6)	O2—Sn1—O2^vi	174.7 (13)
Pb1ⁱⁱⁱ—Pb2—Sn1	61.72 (5)	Pb1^vi—O2—Pb2^vi	145 (2)
Pb1ⁱⁱⁱ—Pb2—Sn1^x	117.54 (7)	Pb1^vi—O2—Sn1	106.6 (15)
Pb1ⁱⁱⁱ—Pb2—O1^iv	100.90 (9)	Pb2^vi—O2—Sn1	109 (2)
Pb1ⁱⁱⁱ—Pb2—O2^vi	52.9 (11)

Symmetry codes: (i) −x+1, −y, z; (ii) −x+1/2, y−1/2, −z; (iii) −x+1/2, y+1/2, −z; (iv) −x+1/2, y−1/2, −z−1; (v) x−1/2, −y+1/2, z; (vi) −x+1, −y+1, z; (vii) −x+1, −y+1, −z; (viii) −x, −y+1, z; (ix) −x+1/2, y+1/2, −z−1; (x) −x+1, −y+1, −z−1; (xi) x+1/2, −y+1/2, −z.

Tin(IV) Dilead Oxide (Pb2SnO4-Pnam-P5) top

Crystal data top

O₄Pb₂Sn	D_x = 10.373 Mg m⁻³
M_r = 597.11	Synchrotron radiation, λ = 0.28988 Å
Orthorhombic, Pnam	Cell parameters from 814 reflections
a = 9.2484 (8) Å	θ = 2.0–17.9°
b = 6.4498 (9) Å	µ = 11.86 mm⁻¹
c = 6.4096 (2) Å	T = 293 K
V = 382.33 (6) Å³	Cuboid, black
Z = 4	0.08 × 0.04 × 0.03 mm
F(000) = 984

Data collection top

Esperanto-CrysAlisPro-abstract goniometer imported esperanto images diffractometer	814 independent reflections
Radiation source: synchrotron	735 reflections with I > 3σ(I)
Synchrotron monochromator	R_int = 0.014
ω scans	θ_max = 17.9°, θ_min = 2.0°
Absorption correction: empirical (using intensity measurements) CrysAlisPro 1.171.39.46 (Rigaku Oxford Diffraction, 2018) Spherical absorption correction using equivalent radius and absorption coefficient. Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.	h = −17→16
T_min = 0.007, T_max = 0.015	k = −8→10
2030 measured reflections	l = −13→13

Refinement top

Refinement on F	Primary atom site location: heavy-atom method
R[F² > 2σ(F²)] = 0.019	Secondary atom site location: difference Fourier map
wR(F²) = 0.024	Weighting scheme based on measured s.u.'s w = 1/(σ²(F) + 0.0001F²)
S = 1.16	(Δ/σ)_max = 0.010
814 reflections	Δρ_max = 1.13 e Å⁻³
38 parameters	Δρ_min = −1.11 e Å⁻³
0 restraints	Extinction correction: B-C type 1 Gaussian isotropic (Becker & Coppens, 1974)
0 constraints	Extinction coefficient: 820 (30)

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Pb1	0.325842 (16)	0.04839 (4)	−0.00841 (2)	0.01372 (7)
Sn1	0.50457 (3)	0.48903 (7)	0.25	0.00925 (11)
O1	0.3216 (4)	0.3172 (9)	0.25	0.0136 (16)
O2	0.7014 (4)	0.6250 (8)	0.25	0.0113 (13)
O3	0.4177 (3)	0.6679 (7)	0.4877 (4)	0.0111 (10)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Pb1	0.01156 (10)	0.01859 (17)	0.01101 (6)	−0.00029 (4)	0.00021 (4)	0.00015 (5)
Sn1	0.00920 (16)	0.0102 (3)	0.00836 (10)	−0.00039 (9)	0	0
O1	0.015 (2)	0.014 (4)	0.0119 (11)	−0.0022 (12)	0	0
O2	0.0111 (19)	0.011 (3)	0.0119 (11)	−0.0015 (11)	0	0
O3	0.0113 (14)	0.012 (2)	0.0104 (8)	0.0005 (8)	0.0007 (8)	0.0006 (10)

Geometric parameters (Å, º) top

Pb1—Pb1ⁱ	3.5185 (9)	Pb1—O3^vii	2.381 (3)
Pb1—Pb1ⁱⁱ	3.5185 (9)	Sn1—Sn1^viii	3.2090 (2)
Pb1—Pb1ⁱⁱⁱ	3.2831 (6)	Sn1—Sn1^ix	3.2090 (2)
Pb1—Pb1^iv	3.0970 (3)	Sn1—O1	2.023 (4)
Pb1—Pb1^v	3.3126 (3)	Sn1—O2	2.021 (4)
Pb1—Sn1ⁱ	3.4471 (6)	Sn1—O3	2.073 (3)
Pb1—Sn1^vi	3.4103 (5)	Sn1—O3^viii	2.090 (3)
Pb1—O1	2.398 (4)	Sn1—O3^x	2.090 (3)
Pb1—O2^vi	2.306 (3)	Sn1—O3^v	2.073 (3)

Pb1ⁱ—Pb1—Pb1ⁱⁱ	132.858 (9)	Pb1^xi—Sn1—O1	133.64 (11)
Pb1ⁱ—Pb1—Pb1ⁱⁱⁱ	102.471 (10)	Pb1^xi—Sn1—O2	41.04 (9)
Pb1ⁱ—Pb1—Pb1^iv	91.756 (7)	Pb1^xi—Sn1—O3	91.15 (8)
Pb1ⁱ—Pb1—Pb1^v	88.244 (7)	Pb1^xi—Sn1—O3^viii	93.25 (8)
Pb1ⁱ—Pb1—Sn1ⁱ	63.801 (9)	Pb1^xi—Sn1—O3^x	43.56 (9)
Pb1ⁱ—Pb1—Sn1^vi	64.715 (9)	Pb1^xi—Sn1—O3^v	137.22 (9)
Pb1ⁱ—Pb1—O1	129.42 (9)	Pb1^xii—Sn1—Pb1^xiii	176.766 (12)
Pb1ⁱ—Pb1—O2^vi	48.28 (10)	Pb1^xii—Sn1—Sn1^viii	62.679 (7)
Pb1ⁱ—Pb1—O3^vii	85.40 (11)	Pb1^xii—Sn1—Sn1^ix	120.738 (9)
Pb1ⁱⁱ—Pb1—Pb1ⁱⁱⁱ	124.366 (9)	Pb1^xii—Sn1—O1	133.64 (11)
Pb1ⁱⁱ—Pb1—Pb1^iv	91.756 (7)	Pb1^xii—Sn1—O2	41.04 (9)
Pb1ⁱⁱ—Pb1—Pb1^v	88.244 (7)	Pb1^xii—Sn1—O3	137.22 (9)
Pb1ⁱⁱ—Pb1—Sn1ⁱ	76.238 (10)	Pb1^xii—Sn1—O3^viii	43.56 (9)
Pb1ⁱⁱ—Pb1—Sn1^vi	72.699 (10)	Pb1^xii—Sn1—O3^x	93.25 (8)
Pb1ⁱⁱ—Pb1—O1	46.34 (9)	Pb1^xii—Sn1—O3^v	91.15 (8)
Pb1ⁱⁱ—Pb1—O2^vi	102.91 (12)	Pb1^xiii—Sn1—Sn1^viii	114.859 (9)
Pb1ⁱⁱ—Pb1—O3^vii	47.65 (11)	Pb1^xiii—Sn1—Sn1^ix	61.518 (7)
Pb1ⁱⁱⁱ—Pb1—Pb1^iv	91.882 (5)	Pb1^xiii—Sn1—O1	47.10 (12)
Pb1ⁱⁱⁱ—Pb1—Pb1^v	88.118 (5)	Pb1^xiii—Sn1—O2	138.63 (10)
Pb1ⁱⁱⁱ—Pb1—Sn1ⁱ	149.708 (9)	Pb1^xiii—Sn1—O3	42.65 (9)
Pb1ⁱⁱⁱ—Pb1—Sn1^vi	145.638 (8)	Pb1^xiii—Sn1—O3^viii	136.06 (8)
Pb1ⁱⁱⁱ—Pb1—O1	97.52 (9)	Pb1^xiii—Sn1—O3^x	89.85 (8)
Pb1ⁱⁱⁱ—Pb1—O2^vi	111.96 (9)	Pb1^xiii—Sn1—O3^v	85.69 (8)
Pb1ⁱⁱⁱ—Pb1—O3^vii	171.97 (10)	Sn1^viii—Sn1—Sn1^ix	174.111 (18)
Pb1^iv—Pb1—Pb1^v	180.0 (5)	Sn1^viii—Sn1—O1	90.122 (11)
Pb1^iv—Pb1—Sn1ⁱ	63.306 (5)	Sn1^viii—Sn1—O2	90.263 (11)
Pb1^iv—Pb1—Sn1^vi	119.057 (6)	Sn1^viii—Sn1—O3	134.36 (10)
Pb1^iv—Pb1—O1	133.68 (10)	Sn1^viii—Sn1—O3^viii	39.38 (10)
Pb1^iv—Pb1—O2^vi	135.91 (8)	Sn1^viii—Sn1—O3^x	146.49 (10)
Pb1^iv—Pb1—O3^vii	89.40 (6)	Sn1^viii—Sn1—O3^v	39.76 (10)
Pb1^v—Pb1—Sn1ⁱ	116.694 (6)	Sn1^ix—Sn1—O1	90.122 (11)
Pb1^v—Pb1—Sn1^vi	60.943 (5)	Sn1^ix—Sn1—O2	90.263 (11)
Pb1^v—Pb1—O1	46.32 (10)	Sn1^ix—Sn1—O3	39.76 (10)
Pb1^v—Pb1—O2^vi	44.09 (8)	Sn1^ix—Sn1—O3^viii	146.49 (10)
Pb1^v—Pb1—O3^vii	90.60 (6)	Sn1^ix—Sn1—O3^x	39.38 (10)
Sn1ⁱ—Pb1—Sn1^vi	55.802 (6)	Sn1^ix—Sn1—O3^v	134.36 (10)
Sn1ⁱ—Pb1—O1	112.09 (9)	O1—Sn1—O2	172.5 (2)
Sn1ⁱ—Pb1—O2^vi	80.00 (8)	O1—Sn1—O3	88.89 (14)
Sn1ⁱ—Pb1—O3^vii	36.15 (8)	O1—Sn1—O3^viii	91.28 (13)
Sn1^vi—Pb1—O1	72.63 (9)	O1—Sn1—O3^x	91.28 (13)
Sn1^vi—Pb1—O2^vi	35.12 (10)	O1—Sn1—O3^v	88.89 (14)
Sn1^vi—Pb1—O3^vii	37.22 (8)	O2—Sn1—O3	96.18 (13)
O1—Pb1—O2^vi	81.16 (14)	O2—Sn1—O3^viii	84.28 (12)
O1—Pb1—O3^vii	75.98 (12)	O2—Sn1—O3^x	84.28 (12)
O2^vi—Pb1—O3^vii	72.08 (13)	O2—Sn1—O3^v	96.18 (13)
Pb1ⁱⁱ—Sn1—Pb1^xi	176.766 (12)	O3—Sn1—O3^viii	173.74 (14)
Pb1ⁱⁱ—Sn1—Pb1^xii	124.198 (5)	O3—Sn1—O3^x	79.14 (14)
Pb1ⁱⁱ—Sn1—Pb1^xiii	53.388 (7)	O3—Sn1—O3^v	94.60 (14)
Pb1ⁱⁱ—Sn1—Sn1^viii	61.518 (7)	O3^viii—Sn1—O3^x	107.11 (14)
Pb1ⁱⁱ—Sn1—Sn1^ix	114.859 (9)	O3^viii—Sn1—O3^v	79.14 (14)
Pb1ⁱⁱ—Sn1—O1	47.10 (12)	O3^x—Sn1—O3^v	173.74 (14)
Pb1ⁱⁱ—Sn1—O2	138.63 (10)	Pb1—O1—Pb1^v	87.37 (19)
Pb1ⁱⁱ—Sn1—O3	85.69 (8)	Pb1—O1—Sn1	112.48 (13)
Pb1ⁱⁱ—Sn1—O3^viii	89.85 (8)	Pb1^v—O1—Sn1	112.48 (13)
Pb1ⁱⁱ—Sn1—O3^x	136.06 (8)	Pb1^xi—O2—Pb1^xii	91.81 (16)
Pb1ⁱⁱ—Sn1—O3^v	42.65 (9)	Pb1^xi—O2—Sn1	103.83 (17)
Pb1^xi—Sn1—Pb1^xii	58.114 (7)	Pb1^xii—O2—Sn1	103.83 (17)
Pb1^xi—Sn1—Pb1^xiii	124.198 (5)	Pb1^xiii—O3—Sn1	101.20 (15)
Pb1^xi—Sn1—Sn1^viii	120.738 (9)	Pb1^xiii—O3—Sn1^ix	99.22 (14)
Pb1^xi—Sn1—Sn1^ix	62.679 (7)	Sn1—O3—Sn1^ix	100.86 (17)

Symmetry codes: (i) −x+1/2, y−1/2, −z; (ii) −x+1/2, y+1/2, −z; (iii) −x+1, −y, −z; (iv) x, y, −z−1/2; (v) x, y, −z+1/2; (vi) x−1/2, −y+1/2, −z+1/2; (vii) −x+1/2, y−1/2, z−1/2; (viii) −x+1, −y+1, z−1/2; (ix) −x+1, −y+1, z+1/2; (x) −x+1, −y+1, −z+1; (xi) x+1/2, −y+1/2, −z+1/2; (xii) x+1/2, −y+1/2, z; (xiii) −x+1/2, y+1/2, z+1/2.

Tin(IV) Dilead Oxide (Pb2SnO4-Pnam-P6) top

Crystal data top

O₄Pb₂Sn	D_x = 10.582 Mg m⁻³
M_r = 597.11	Synchrotron radiation, λ = 0.28988 Å
Orthorhombic, Pnam	Cell parameters from 814 reflections
a = 9.1830 (6) Å	θ = 2.1–18.1°
b = 6.4046 (6) Å	µ = 12.10 mm⁻¹
c = 6.3727 (2) Å	T = 293 K
V = 374.80 (4) Å³	Cuboid, black
Z = 4	0.08 × 0.04 × 0.03 mm
F(000) = 984

Data collection top

Esperanto-CrysAlisPro-abstract goniometer imported esperanto images diffractometer	814 independent reflections
Radiation source: synchrotron	710 reflections with I > 3σ(I)
Synchrotron monochromator	R_int = 0.016
ω scans	θ_max = 18.1°, θ_min = 2.1°
Absorption correction: empirical (using intensity measurements) CrysAlisPro 1.171.39.46 (Rigaku Oxford Diffraction, 2018) Spherical absorption correction using equivalent radius and absorption coefficient. Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.	h = −17→16
T_min = 0.007, T_max = 0.015	k = −8→9
1973 measured reflections	l = −13→12

Refinement top

Refinement on F	Primary atom site location: heavy-atom method
R[F² > 2σ(F²)] = 0.020	Secondary atom site location: difference Fourier map
wR(F²) = 0.028	Weighting scheme based on measured s.u.'s w = 1/(σ²(F) + 0.0001F²)
S = 1.35	(Δ/σ)_max = 0.019
814 reflections	Δρ_max = 0.55 e Å⁻³
38 parameters	Δρ_min = −0.98 e Å⁻³
0 restraints	Extinction correction: B-C type 1 Gaussian isotropic (Becker & Coppens, 1974)
0 constraints	Extinction coefficient: 350 (30)

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Pb1	0.32743 (2)	0.04860 (4)	−0.00895 (3)	0.01368 (8)
Sn1	0.50478 (4)	0.48900 (9)	0.25	0.01019 (14)
O1	0.3213 (5)	0.3176 (11)	0.25	0.0119 (18)
O2	0.7025 (5)	0.6253 (10)	0.25	0.0110 (17)
O3	0.4171 (4)	0.6684 (8)	0.4877 (5)	0.0120 (12)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Pb1	0.01159 (12)	0.0170 (2)	0.01240 (8)	−0.00029 (4)	0.00023 (5)	0.00012 (6)
Sn1	0.0095 (2)	0.0113 (4)	0.00980 (13)	−0.00047 (11)	0	0
O1	0.015 (3)	0.007 (4)	0.0138 (15)	−0.0021 (13)	0	0
O2	0.013 (2)	0.007 (4)	0.0131 (15)	−0.0008 (13)	0	0
O3	0.0156 (18)	0.008 (3)	0.0128 (11)	0.0016 (10)	−0.0002 (10)	−0.0006 (14)

Geometric parameters (Å, º) top

Pb1—Pb1ⁱ	3.5057 (7)	Pb1—O3^vii	2.373 (4)
Pb1—Pb1ⁱⁱ	3.5057 (7)	Sn1—Sn1^viii	3.1907 (2)
Pb1—Pb1ⁱⁱⁱ	3.2320 (5)	Sn1—Sn1^ix	3.1907 (2)
Pb1—Pb1^iv	3.0723 (3)	Sn1—O1	2.011 (5)
Pb1—Pb1^v	3.3004 (3)	Sn1—O2	2.015 (5)
Pb1—Sn1ⁱ	3.4369 (5)	Sn1—O3	2.065 (4)
Pb1—Sn1^vi	3.4000 (5)	Sn1—O3^viii	2.080 (4)
Pb1—O1	2.386 (5)	Sn1—O3^x	2.080 (4)
Pb1—O2^vi	2.298 (4)	Sn1—O3^v	2.065 (4)

Pb1ⁱ—Pb1—Pb1ⁱⁱ	131.973 (9)	Pb1^xi—Sn1—O1	133.75 (14)
Pb1ⁱ—Pb1—Pb1ⁱⁱⁱ	102.750 (9)	Pb1^xi—Sn1—O2	41.00 (12)
Pb1ⁱ—Pb1—Pb1^iv	91.865 (8)	Pb1^xi—Sn1—O3	91.33 (10)
Pb1ⁱ—Pb1—Pb1^v	88.135 (7)	Pb1^xi—Sn1—O3^viii	93.16 (10)
Pb1ⁱ—Pb1—Sn1ⁱ	63.450 (11)	Pb1^xi—Sn1—O3^x	43.53 (11)
Pb1ⁱ—Pb1—Sn1^vi	64.279 (11)	Pb1^xi—Sn1—O3^v	137.34 (11)
Pb1ⁱ—Pb1—O1	128.86 (12)	Pb1^xii—Sn1—Pb1^xiii	176.681 (15)
Pb1ⁱ—Pb1—O2^vi	48.04 (13)	Pb1^xii—Sn1—Sn1^viii	62.768 (8)
Pb1ⁱ—Pb1—O3^vii	84.94 (12)	Pb1^xii—Sn1—Sn1^ix	120.784 (12)
Pb1ⁱⁱ—Pb1—Pb1ⁱⁱⁱ	124.931 (9)	Pb1^xii—Sn1—O1	133.75 (14)
Pb1ⁱⁱ—Pb1—Pb1^iv	91.865 (8)	Pb1^xii—Sn1—O2	41.00 (12)
Pb1ⁱⁱ—Pb1—Pb1^v	88.135 (7)	Pb1^xii—Sn1—O3	137.34 (11)
Pb1ⁱⁱ—Pb1—Sn1ⁱ	75.873 (11)	Pb1^xii—Sn1—O3^viii	43.53 (11)
Pb1ⁱⁱ—Pb1—Sn1^vi	72.266 (11)	Pb1^xii—Sn1—O3^x	93.16 (10)
Pb1ⁱⁱ—Pb1—O1	46.25 (11)	Pb1^xii—Sn1—O3^v	91.33 (10)
Pb1ⁱⁱ—Pb1—O2^vi	102.52 (15)	Pb1^xiii—Sn1—Sn1^viii	114.647 (12)
Pb1ⁱⁱ—Pb1—O3^vii	47.24 (12)	Pb1^xiii—Sn1—Sn1^ix	61.596 (8)
Pb1ⁱⁱⁱ—Pb1—Pb1^iv	92.023 (7)	Pb1^xiii—Sn1—O1	46.91 (14)
Pb1ⁱⁱⁱ—Pb1—Pb1^v	87.977 (7)	Pb1^xiii—Sn1—O2	138.75 (13)
Pb1ⁱⁱⁱ—Pb1—Sn1ⁱ	149.863 (10)	Pb1^xiii—Sn1—O3	42.62 (11)
Pb1ⁱⁱⁱ—Pb1—Sn1^vi	145.467 (10)	Pb1^xiii—Sn1—O3^viii	135.99 (11)
Pb1ⁱⁱⁱ—Pb1—O1	97.92 (11)	Pb1^xiii—Sn1—O3^x	90.04 (10)
Pb1ⁱⁱⁱ—Pb1—O2^vi	111.77 (12)	Pb1^xiii—Sn1—O3^v	85.41 (10)
Pb1ⁱⁱⁱ—Pb1—O3^vii	172.10 (12)	Sn1^viii—Sn1—Sn1^ix	174.04 (2)
Pb1^iv—Pb1—Pb1^v	180.0 (5)	Sn1^viii—Sn1—O1	90.060 (15)
Pb1^iv—Pb1—Sn1ⁱ	63.451 (6)	Sn1^viii—Sn1—O2	90.324 (14)
Pb1^iv—Pb1—Sn1^vi	119.036 (8)	Sn1^viii—Sn1—O3	134.22 (12)
Pb1^iv—Pb1—O1	133.75 (12)	Sn1^viii—Sn1—O3^viii	39.49 (12)
Pb1^iv—Pb1—O2^vi	135.90 (10)	Sn1^viii—Sn1—O3^x	146.47 (12)
Pb1^iv—Pb1—O3^vii	89.48 (8)	Sn1^viii—Sn1—O3^v	39.83 (11)
Pb1^v—Pb1—Sn1ⁱ	116.549 (7)	Sn1^ix—Sn1—O1	90.060 (15)
Pb1^v—Pb1—Sn1^vi	60.964 (6)	Sn1^ix—Sn1—O2	90.324 (14)
Pb1^v—Pb1—O1	46.25 (12)	Sn1^ix—Sn1—O3	39.83 (11)
Pb1^v—Pb1—O2^vi	44.10 (10)	Sn1^ix—Sn1—O3^viii	146.47 (12)
Pb1^v—Pb1—O3^vii	90.52 (8)	Sn1^ix—Sn1—O3^x	39.49 (12)
Sn1ⁱ—Pb1—Sn1^vi	55.636 (6)	Sn1^ix—Sn1—O3^v	134.22 (12)
Sn1ⁱ—Pb1—O1	111.61 (11)	O1—Sn1—O2	172.6 (3)
Sn1ⁱ—Pb1—O2^vi	79.86 (9)	O1—Sn1—O3	88.68 (17)
Sn1ⁱ—Pb1—O3^vii	36.10 (10)	O1—Sn1—O3^viii	91.40 (16)
Sn1^vi—Pb1—O1	72.24 (11)	O1—Sn1—O3^x	91.40 (16)
Sn1^vi—Pb1—O2^vi	35.12 (13)	O1—Sn1—O3^v	88.68 (17)
Sn1^vi—Pb1—O3^vii	37.12 (9)	O2—Sn1—O3	96.33 (16)
O1—Pb1—O2^vi	80.88 (17)	O2—Sn1—O3^viii	84.21 (15)
O1—Pb1—O3^vii	75.55 (15)	O2—Sn1—O3^x	84.21 (15)
O2^vi—Pb1—O3^vii	71.99 (16)	O2—Sn1—O3^v	96.33 (16)
Pb1ⁱⁱ—Sn1—Pb1^xi	176.680 (15)	O3—Sn1—O3^viii	173.70 (17)
Pb1ⁱⁱ—Sn1—Pb1^xii	124.364 (6)	O3—Sn1—O3^x	79.31 (16)
Pb1ⁱⁱ—Sn1—Pb1^xiii	53.097 (8)	O3—Sn1—O3^v	94.39 (16)
Pb1ⁱⁱ—Sn1—Sn1^viii	61.596 (8)	O3^viii—Sn1—O3^x	106.98 (17)
Pb1ⁱⁱ—Sn1—Sn1^ix	114.647 (12)	O3^viii—Sn1—O3^v	79.31 (16)
Pb1ⁱⁱ—Sn1—O1	46.91 (14)	O3^x—Sn1—O3^v	173.70 (17)
Pb1ⁱⁱ—Sn1—O2	138.75 (13)	Pb1—O1—Pb1^v	87.5 (2)
Pb1ⁱⁱ—Sn1—O3	85.41 (10)	Pb1—O1—Sn1	111.98 (16)
Pb1ⁱⁱ—Sn1—O3^viii	90.04 (10)	Pb1^v—O1—Sn1	111.98 (16)
Pb1ⁱⁱ—Sn1—O3^x	135.99 (11)	Pb1^xi—O2—Pb1^xii	91.8 (2)
Pb1ⁱⁱ—Sn1—O3^v	42.62 (11)	Pb1^xi—O2—Sn1	103.9 (2)
Pb1^xi—Sn1—Pb1^xii	58.072 (8)	Pb1^xii—O2—Sn1	103.9 (2)
Pb1^xi—Sn1—Pb1^xiii	124.364 (6)	Pb1^xiii—O3—Sn1	101.28 (17)
Pb1^xi—Sn1—Sn1^viii	120.784 (12)	Pb1^xiii—O3—Sn1^ix	99.35 (16)
Pb1^xi—Sn1—Sn1^ix	62.768 (8)	Sn1—O3—Sn1^ix	100.7 (2)

Tin(IV) Dilead Oxide (Pb2SnO4-Pnam-P7) top

Crystal data top

O₄Pb₂Sn	D_x = 10.950 Mg m⁻³
M_r = 597.11	Synchrotron radiation, λ = 0.28988 Å
Orthorhombic, Pnam	Cell parameters from 813 reflections
a = 9.0691 (6) Å	θ = 1.6–17.8°
b = 6.3282 (6) Å	µ = 12.52 mm⁻¹
c = 6.3110 (2) Å	T = 293 K
V = 362.20 (4) Å³	Cuboid, black
Z = 4	0.08 × 0.04 × 0.03 mm
F(000) = 984

Data collection top

Esperanto-CrysAlisPro-abstract goniometer imported esperanto images diffractometer	813 independent reflections
Radiation source: synchrotron	709 reflections with I > 3σ(I)
Synchrotron monochromator	R_int = 0.017
ω scans	θ_max = 17.8°, θ_min = 1.6°
Absorption correction: empirical (using intensity measurements) CrysAlisPro 1.171.39.46 (Rigaku Oxford Diffraction, 2018) Spherical absorption correction using equivalent radius and absorption coefficient. Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm.	h = −17→16
T_min = 0.007, T_max = 0.015	k = −9→8
1940 measured reflections	l = −12→12

Refinement top

Refinement on F	Primary atom site location: heavy-atom method
R[F² > 2σ(F²)] = 0.024	Secondary atom site location: difference Fourier map
wR(F²) = 0.030	Weighting scheme based on measured s.u.'s w = 1/(σ²(F) + 0.0001F²)
S = 1.41	(Δ/σ)_max = 0.003
813 reflections	Δρ_max = 0.64 e Å⁻³
38 parameters	Δρ_min = −0.71 e Å⁻³
0 restraints	Extinction correction: B-C type 1 Gaussian isotropic (Becker & Coppens, 1974)
0 constraints	Extinction coefficient: 330 (40)

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Pb1	0.329942 (19)	0.04924 (4)	−0.01000 (3)	0.01364 (8)
Sn1	0.50515 (4)	0.48897 (9)	0.25	0.01117 (14)
O1	0.3188 (5)	0.3174 (11)	0.25	0.0130 (18)
O2	0.7045 (6)	0.6259 (10)	0.25	0.0141 (18)
O3	0.4172 (4)	0.6707 (8)	0.4877 (5)	0.0128 (12)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Pb1	0.01235 (12)	0.0159 (2)	0.01263 (8)	−0.00023 (4)	0.00012 (4)	0.00002 (6)
Sn1	0.0107 (2)	0.0129 (4)	0.00992 (13)	−0.00042 (12)	0	0
O1	0.014 (2)	0.013 (4)	0.0121 (14)	−0.0022 (14)	0	0
O2	0.014 (3)	0.014 (4)	0.0142 (16)	−0.0011 (14)	0	0
O3	0.0140 (17)	0.012 (3)	0.0122 (10)	0.0023 (10)	0.0014 (9)	0.0012 (12)

Geometric parameters (Å, º) top

Pb1—Pb1ⁱ	3.4825 (6)	Pb1—O3^vii	2.369 (4)
Pb1—Pb1ⁱⁱ	3.4825 (6)	Sn1—Sn1^viii	3.1600 (2)
Pb1—Pb1ⁱⁱⁱ	3.1493 (5)	Sn1—Sn1^ix	3.1600 (2)
Pb1—Pb1^iv	3.0293 (3)	Sn1—O1	2.009 (5)
Pb1—Pb1^v	3.2817 (3)	Sn1—O2	2.005 (6)
Pb1—Sn1ⁱ	3.4168 (5)	Sn1—O3	2.052 (4)
Pb1—Sn1^vi	3.3804 (5)	Sn1—O3^viii	2.063 (4)
Pb1—O1	2.363 (5)	Sn1—O3^x	2.063 (4)
Pb1—O2^vi	2.284 (4)	Sn1—O3^v	2.052 (4)

Pb1ⁱ—Pb1—Pb1ⁱⁱ	130.592 (8)	Pb1^xi—Sn1—O1	133.98 (13)
Pb1ⁱ—Pb1—Pb1ⁱⁱⁱ	103.095 (9)	Pb1^xi—Sn1—O2	40.99 (12)
Pb1ⁱ—Pb1—Pb1^iv	92.077 (8)	Pb1^xi—Sn1—O3	91.37 (10)
Pb1ⁱ—Pb1—Pb1^v	87.923 (7)	Pb1^xi—Sn1—O3^viii	93.27 (10)
Pb1ⁱ—Pb1—Sn1ⁱ	62.894 (10)	Pb1^xi—Sn1—O3^x	43.79 (11)
Pb1ⁱ—Pb1—Sn1^vi	63.553 (11)	Pb1^xi—Sn1—O3^v	137.21 (11)
Pb1ⁱ—Pb1—O1	127.55 (12)	Pb1^xii—Sn1—Pb1^xiii	176.511 (14)
Pb1ⁱ—Pb1—O2^vi	47.60 (13)	Pb1^xii—Sn1—Sn1^viii	62.883 (8)
Pb1ⁱ—Pb1—O3^vii	84.32 (12)	Pb1^xii—Sn1—Sn1^ix	120.907 (12)
Pb1ⁱⁱ—Pb1—Pb1ⁱⁱⁱ	125.880 (9)	Pb1^xii—Sn1—O1	133.98 (13)
Pb1ⁱⁱ—Pb1—Pb1^iv	92.077 (8)	Pb1^xii—Sn1—O2	40.99 (12)
Pb1ⁱⁱ—Pb1—Pb1^v	87.923 (7)	Pb1^xii—Sn1—O3	137.21 (11)
Pb1ⁱⁱ—Pb1—Sn1ⁱ	75.354 (11)	Pb1^xii—Sn1—O3^viii	43.79 (11)
Pb1ⁱⁱ—Pb1—Sn1^vi	71.614 (11)	Pb1^xii—Sn1—O3^x	93.27 (10)
Pb1ⁱⁱ—Pb1—O1	45.94 (11)	Pb1^xii—Sn1—O3^v	91.37 (10)
Pb1ⁱⁱ—Pb1—O2^vi	101.97 (15)	Pb1^xiii—Sn1—Sn1^viii	114.295 (12)
Pb1ⁱⁱ—Pb1—O3^vii	46.51 (12)	Pb1^xiii—Sn1—Sn1^ix	61.713 (8)
Pb1ⁱⁱⁱ—Pb1—Pb1^iv	92.297 (7)	Pb1^xiii—Sn1—O1	46.53 (14)
Pb1ⁱⁱⁱ—Pb1—Pb1^v	87.703 (6)	Pb1^xiii—Sn1—O2	138.92 (13)
Pb1ⁱⁱⁱ—Pb1—Sn1ⁱ	150.085 (10)	Pb1^xiii—Sn1—O3	42.90 (11)
Pb1ⁱⁱⁱ—Pb1—Sn1^vi	145.066 (10)	Pb1^xiii—Sn1—O3^viii	135.55 (11)
Pb1ⁱⁱⁱ—Pb1—O1	98.98 (11)	Pb1^xiii—Sn1—O3^x	90.15 (10)
Pb1ⁱⁱⁱ—Pb1—O2^vi	111.29 (13)	Pb1^xiii—Sn1—O3^v	85.17 (10)
Pb1ⁱⁱⁱ—Pb1—O3^vii	172.25 (12)	Sn1^viii—Sn1—Sn1^ix	173.91 (2)
Pb1^iv—Pb1—Pb1^v	180.0 (5)	Sn1^viii—Sn1—O1	89.943 (15)
Pb1^iv—Pb1—Sn1ⁱ	63.686 (6)	Sn1^viii—Sn1—O2	90.434 (14)
Pb1^iv—Pb1—Sn1^vi	119.039 (7)	Sn1^viii—Sn1—O3	133.94 (11)
Pb1^iv—Pb1—O1	133.99 (12)	Sn1^viii—Sn1—O3^viii	39.69 (12)
Pb1^iv—Pb1—O2^vi	135.93 (11)	Sn1^viii—Sn1—O3^x	146.40 (12)
Pb1^iv—Pb1—O3^vii	89.65 (8)	Sn1^viii—Sn1—O3^v	39.97 (11)
Pb1^v—Pb1—Sn1ⁱ	116.314 (7)	Sn1^ix—Sn1—O1	89.943 (15)
Pb1^v—Pb1—Sn1^vi	60.961 (6)	Sn1^ix—Sn1—O2	90.434 (14)
Pb1^v—Pb1—O1	46.01 (12)	Sn1^ix—Sn1—O3	39.97 (11)
Pb1^v—Pb1—O2^vi	44.07 (11)	Sn1^ix—Sn1—O3^viii	146.40 (12)
Pb1^v—Pb1—O3^vii	90.35 (8)	Sn1^ix—Sn1—O3^x	39.69 (12)
Sn1ⁱ—Pb1—Sn1^vi	55.404 (6)	Sn1^ix—Sn1—O3^v	133.94 (11)
Sn1ⁱ—Pb1—O1	110.49 (11)	O1—Sn1—O2	172.9 (3)
Sn1ⁱ—Pb1—O2^vi	79.70 (11)	O1—Sn1—O3	88.62 (17)
Sn1ⁱ—Pb1—O3^vii	36.12 (10)	O1—Sn1—O3^viii	91.29 (16)
Sn1^vi—Pb1—O1	71.15 (11)	O1—Sn1—O3^x	91.29 (16)
Sn1^vi—Pb1—O2^vi	35.16 (14)	O1—Sn1—O3^v	88.62 (17)
Sn1^vi—Pb1—O3^vii	37.06 (9)	O2—Sn1—O3	96.22 (17)
O1—Pb1—O2^vi	80.11 (18)	O2—Sn1—O3^viii	84.48 (15)
O1—Pb1—O3^vii	74.39 (15)	O2—Sn1—O3^x	84.48 (15)
O2^vi—Pb1—O3^vii	71.98 (17)	O2—Sn1—O3^v	96.22 (17)
Pb1ⁱⁱ—Sn1—Pb1^xi	176.511 (14)	O3—Sn1—O3^viii	173.64 (16)
Pb1ⁱⁱ—Sn1—Pb1^xii	124.596 (6)	O3—Sn1—O3^x	79.66 (16)
Pb1ⁱⁱ—Sn1—Pb1^xiii	52.628 (8)	O3—Sn1—O3^v	93.98 (16)
Pb1ⁱⁱ—Sn1—Sn1^viii	61.713 (8)	O3^viii—Sn1—O3^x	106.70 (17)
Pb1ⁱⁱ—Sn1—Sn1^ix	114.295 (12)	O3^viii—Sn1—O3^v	79.66 (16)
Pb1ⁱⁱ—Sn1—O1	46.53 (14)	O3^x—Sn1—O3^v	173.64 (16)
Pb1ⁱⁱ—Sn1—O2	138.92 (13)	Pb1—O1—Pb1^v	88.0 (2)
Pb1ⁱⁱ—Sn1—O3	85.17 (10)	Pb1—O1—Sn1	110.62 (16)
Pb1ⁱⁱ—Sn1—O3^viii	90.15 (10)	Pb1^v—O1—Sn1	110.62 (16)
Pb1ⁱⁱ—Sn1—O3^x	135.55 (11)	Pb1^xi—O2—Pb1^xii	91.9 (2)
Pb1ⁱⁱ—Sn1—O3^v	42.90 (11)	Pb1^xi—O2—Sn1	103.9 (2)
Pb1^xi—Sn1—Pb1^xii	58.079 (8)	Pb1^xii—O2—Sn1	103.9 (2)
Pb1^xi—Sn1—Pb1^xiii	124.596 (6)	Pb1^xiii—O3—Sn1	100.98 (17)
Pb1^xi—Sn1—Sn1^viii	120.907 (12)	Pb1^xiii—O3—Sn1^ix	99.15 (16)
Pb1^xi—Sn1—Sn1^ix	62.883 (8)	Sn1—O3—Sn1^ix	100.3 (2)

Acknowledgements

The `2n+1' Raman theorem in CASTEP was developed under grant EP/I030107/1. We acknowledge DESY (Hamburg, Germany), a member of the Helmholtz Association HGF, for the provision of experimental facilities. Parts of this research were carried out at PETRA III. Open access funding enabled and organized by Projekt DEAL.

Funding information

Funding for this research was provided by: Deutsche Forschungsgemeinschaft (grant No. Wi1232/44-1; grant No. Wi1232/41-1; grant No. Ba4020; grant No. FOR2125); Bundesministerium für Bildung und Forschung (grant No. 05K16RFB); Engineering and Physical Sciences Research Council (grant No. EP/I030107/1).

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