The crystal structure and magnetic properties of the synthetic langbeinite KBaFe2(PO4)3

doi:10.1016/0022-4596(86)90211-2

Journal of Solid State Chemistry

Volume 62, Issue 1, 15 March 1986, Pages 16-25

https://doi.org/10.1016/0022-4596(86)90211-2 Get rights and content

Abstract

Powder neutron diffraction data have been used to refine the crystal structure of KBaFe₂(PO₄)₃ at 4.2 K; space group P2₁3, a₀ = 9.8732(1) Å. The material is isostructural with the mineral langbeinite, having two crystallographically distinct, octahedrally coordinated Fe³⁺ ions in the asymmetric unit. Mössbauer effect spectroscopy and magnetic susceptibility measurements show that KBaFe₂(PO₄)₃ orders as an L-type ferrimagnet with 3.9 < T_C < 4.2 K. The variation of H_int has been monitored by Mössbauer spectroscopy in the temperature range 1.3 < T < 4.2 K.

References (9)

G.J. Long et al.
Inorg. Chem.
(1979)
P.D. Battle et al.
Inorg. Chem.
(1982)
L. Neel
Ann. Phys.
(1948)
R. Masse
Bull. Soc. Franc. Min. Cryst.
(1972)

There are more references available in the full text version of this article.

Cited by (54)

Synthesis, crystal structure, Mössbauer spectroscopy, optical and magnetic properties of Cs<inf>2</inf>M<inf>2</inf>Fe(PO<inf>4</inf>)<inf>3</inf> (M = Mn, Co, Ni, Cu) ordered pollucite structure
2019, Journal of Solid State Chemistry
Citation Excerpt :
This versatility is essentially due to the double ability of iron to adopt a mixed valence and various coordination polyhedra [FeO]n with n = 4, 5 or 6. According to their chemical formula and the nature of the alkali cation metals, iron monophosphates frameworks are either bi- or three-dimensional and often delimit tunnels or cavities available to the alkali and alkaline earth cations [5–7]. Our main interest in these materials concerns the preparation of new compounds with open framework and the study of their structural and physical properties.
Four isomorphous iron phosphates Cs₂M₂Fe(PO₄)₃ (M = Mn, Co, Ni, Cu) have been synthesized as powder by conventional solid state technic and characterized by X-ray diffraction, magnetic susceptibility, diffuse reflectance and Mössbauer spectroscopies. All these compounds crystallize in the space group I4₁32 of the cubic system with similar cell parameters: a = 13.8268(1) Å, 13.7624(1) Å, 13.5917(1) Å or 13.5834(1) Å for M = Mn, Co, Ni or Cu, respectively and eight formula units per cell. Their structure closely related to that of pollucite, is built up from [M_2/3,Fe_1/3]O₄ tetrahedra connected to each other through the common corners with PO₄ tetrahedra. The resulting anionic three-dimensional framework leads to the formation along [1 1 1] direction, of channels where the large cesium ions occupy two independent crystallographic sites. A Mössbauer study at room temperature, confirmed the +3 oxidation state of iron and its tetrahedral coordination. Diffuse reflectance spectroscopy also confirmed the occurrence of isolated Fe³⁺ ions: low energy gap due to oxygen to iron (III) inter-electronic transition and absence of d-d transition linked to iron; the colorimetric properties of the compounds were shown to be mainly governed by the visible d-d transitions linked to the M²⁺ cation in tetrahedral coordination. Magnetic susceptibility measurements reveal that the title compounds are weakly magnetically ordered at very low temperature due to super-superexchange magnetic interaction. The thermal evolution of χ_m follows in a wide temperature range, a Curie-Weiss law χ = C/(T-θ) with θ = − 59, −36, −50 and −39 K for Mn, Co, Ni and Cu phases, respectively.
Synthesis and characterization of a new iron phosphate KSrFe <inf>2</inf>(PO<inf>4</inf>)<inf>3</inf> with a langbeinite type structure
2012, Journal of Molecular Structure
Citation Excerpt :
Magnetic susceptibility measurements were performed in the 4.2–300 K temperature range by a Quantum Design SQUID MPMS-XL magnetometer at a constant magnetic field of 0.5 T. KSrFe2(PO4)3 is isostructural with the langbeinite-like iron phosphates NaBaFe2(PO4)3 [12] and KBaFe2(PO4)3 [16]. A projection of the structure along the [1 1 1] direction (Fig. 1) shows that the [Fe2(PO4)3]∞ framework is consisted by a three-dimensional assemblage of corner-sharing FeO6 octahedra and PO4 tetrahedra.
Synthesis, crystal structure, Mössbauer spectroscopy and magnetic susceptibility of a new phosphate KSrFe₂(PO₄)₃ are described. This compound crystallizes with the unit cell parameter a = 9.809(2) Å of the cubic space group P2₁3 and four formula units per cell. Its structure belongs to the well known langbeinite type. It consists of a 3D framework resulting from a corner-sharing between FeO₆ octahedra and PO₄ tetrahedra. This framework delimits two distinct cavities, statistically occupied by the K⁺ and Sr²⁺ ions. The Mössbauer spectroscopy gave clear evidence of the exclusive presence of octahedral Fe³⁺ ions. The magnetic susceptibility measurements revealed that the compound follows the Curie–Weiss behavior with an experimental effective moment per unit formula μ = 8.16 μ_B, consistent with the ideal spin only value of 8.37 μ_B.
The layered iron phosphate KMgFe(PO<inf>4</inf>)<inf>2</inf>: Crystal structure, Mössbauer spectroscopy and ionic conductivity
2009, Solid State Ionics
A new iron phosphate, KMgFe(PO₄)₂ has been synthesized and investigated by X-ray diffraction, Mössbauer spectroscopy and ionic conductivity. This compound crystallizes in the monoclinic space group C2/c with the parameters a = 18.529(7) Å, b = 5.402(3) Å, c = 9.374(9) Å, β = 120.64(5)° and Z = 4. Its original structure can be described as the stacking along the [101] direction of [MgFe(PO₄)⁻₂]_∞ layers of corner-sharing MO₄ (M = 0.5 Fe + 0.5 Mg) and PO₄ tetrahedra. The K⁺ ions are occupying the inter-layer space. The Mössbauer spectroscopy confirms the occurrence of only tetrahedral Fe³⁺ ions and gives a definitive proof of the disordered character of their distribution. Ionic conductivity results obtained by the impedance spectroscopy technique show that this material is a two-dimensional ionic conductor, with low activation energy, 0.51 eV, that is interpreted on the basis of two-dimensional pathways.
Crystal and band structure of K<inf>2</inf>AlTi(PO<inf>4</inf>)<inf>3</inf> with the langbeinite-type structure
2009, Journal of Alloys and Compounds
Solid-state reaction of K₂CO₃, Al₂O₃, TiO₂ and NH₄H₂PO₄ at 1000 °C leads to a new dipotassium aluminum titanium phosphate: K₂AlTi(PO₄)₃. Its structure was established by single-crystal X-ray diffraction. The title compound crystallizes in the cubic space group P2₁3 (No. 198) with cell parameters of a = 9.76410(10) Å and V = 930.886(17) Å³. It belongs to the langbeinite [K₂Mg₂(S O₄)₃] structure type and its structure features a three-dimensional anionic network of [AlTi(PO₄)₃]²⁻ interconnected by K⁺ cations. The elemental analysis, IR spectrum and UV-vis absorption spectrum have been investigated. Additionally, we also make the calculations of band structure and density of states with the density functional theory method for the title compound.
Structural study by X-ray diffraction and Mössbauer spectroscopy of a new synthetic iron phosphate: K<inf>4</inf>MgFe<inf>3</inf>(PO<inf>4</inf>) <inf>5</inf>
2008, Journal of Physics and Chemistry of Solids
A new iron phosphate K₄MgFe₃(PO₄)₅ has been synthesized by the flux method and characterized by single-crystal X-ray diffraction and Mössbauer spectroscopy. It crystallizes in the tetragonal system with the space group $P \bar{4} 2_{1} c$ and the unit cell parameters a=9.714(3) Å and c=9.494(5) Å. The crystal structure is of a new type. It exhibits a three-dimensional framework built up from corner-sharing MO₅ (M=0.75Fe+0.25Mg) trigonal bipyramids and PO₄ tetrahedra. The K⁺ ions are occupying large eight-sided tunnels running along c. A room temperature Mössbauer study confirmed the +3 valence state of iron and its five-coordination.
The iron potassium diarsenate KFeAs<inf>2</inf>O<inf>7</inf> structural, electric and magnetic behaviors
2007, Journal of Solid State Chemistry
Crystals of a new potassium iron (III) diarsenate (KFeAs₂O₇) have been grown and characterized by single crystal X-ray diffraction. It crystallizes in the triclinic space group $P \bar{1}$ , with a=7.662(1) Å, b=8.402(2) Å, c=10.100(3) Å, α=90.42(3)°, β=89.74(2)°, γ=106.39(2)°, V=623.8(3) Å³ and Z=4. The final agreement factors are R=0.0342, wR=0.0889, S(F²)=1.01; the structural model is validated by bond valence sum (BVS) and charge distribution (CD) methods. The structure consists of corner-sharing FeO₆ octahedra and As₂O₇ diarsenate groups, the three-dimensional framework delimits tunnels running along [0 1 0] direction where the potassium ions reside. The crystal structure of the title compound is different from that of the monoclinic KAlP₂O₇ type but structural relationships exist between the frameworks. Impedance measurements (frequency/temperature ranges: 5–13,000 Hz/526–668 K) show KFeAs₂O₇ an ionic conductor being the conductivity 2.76×10⁻⁷ S cm⁻¹ at 568 K and E_a is 0.47 eV. The BVS model suggests that the most probable potassium conduction pathway is along b-direction. Magnetic measurements reveal the Curie—Weiss type paramagnetic behavior over the range 30–300 K and ferromagnetic below 29.3 K.

View all citing articles on Scopus

View full text

The crystal structure and magnetic properties of the synthetic langbeinite KBaFe2(PO4)3

Abstract

Inorg. Chem.

Inorg. Chem.

Ann. Phys.

Bull. Soc. Franc. Min. Cryst.

The crystal structure and magnetic properties of the synthetic langbeinite KBaFe₂(PO₄)₃