Materials Data on Pr4As2S9 by Materials Project
Pr4As2S9 crystallizes in the orthorhombic Pbcn space group. The structure is three-dimensional. there are two inequivalent Pr3+ sites. In the first Pr3+ site, Pr3+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Pr–S bond distances ranging from 2.87–3.29 Å. In the second Pr3+ site, Pr3+ is bonded to seven S2- atoms to form a mixture of distorted corner and edge-sharing PrS7 pentagonal bipyramids. There are a spread of Pr–S bond distances ranging from 2.84–3.04 Å. As3+ is bonded in a distorted trigonal non-coplanar geometry to three S2- atoms. There are one shorter (2.27 Å) and two longer (2.30 Å) As–S bond lengths. There are five inequivalent S2- sites. In the first S2- site, S2- is bonded in a 3-coordinate geometry to three equivalent Pr3+ and one As3+ atom. In the second S2- site, S2- is bonded in a distorted see-saw-like geometry to three Pr3+ and one As3+ atom. In the third S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to three Pr3+ and one As3+ atom. In the fourth S2- site, S2- is bonded to four equivalent Pr3+ atoms to form distorted edge-sharing SPr4 tetrahedra. In the fifth S2- site, S2- is bonded to four equivalent Pr3+ atoms to form a mixture of distorted corner and edge-sharing SPr4 tetrahedra.