The structure of the ${\mathrm{SnB}}_2{\mathrm{O}}_4$ glass has been investigated using neutron diffraction and reverse Monte Carlo modeling. Three different model configurations were produced, each with different coordination states for the boron atoms. It was found that 3–3.5 fold, in average, coordination for the boron atoms gave excellent agreement with the experimental structure factor, whereas fourfold coordination gave poor agreement. The partial structure factors suggest that Sn atoms form directional bonds and on average bridge between the neighboring borate units. This coordination behavior was also confirmed in an additional simulation, with predetermined Sn coordination, which showed good agreement between the produced model and the experimental data. Sn is, therefore, suggested to act more like a network glass former than simply as a network modifier.

• Received 19 December 2001

DOI:https://doi.org/10.1103/PhysRevB.65.212201