Materials Data on La2Si2PbSe8 by Materials Project
La2PbSi2Se8 crystallizes in the monoclinic Cc space group. The structure is three-dimensional. there are two inequivalent La3+ sites. In the first La3+ site, La3+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of La–Se bond distances ranging from 2.98–3.32 Å. In the second La3+ site, La3+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of La–Se bond distances ranging from 2.98–3.34 Å. Pb2+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of Pb–Se bond distances ranging from 2.95–3.67 Å. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded in a tetrahedral geometry to four Se2- atoms. There are three shorter (2.29 Å) and one longer (2.31 Å) Si–Se bond lengths. In the second Si4+ site, Si4+ is bonded in a tetrahedral geometry to four Se2- atoms. There are three shorter (2.29 Å) and one longer (2.30 Å) Si–Se bond lengths. There are eight inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 4-coordinate geometry to two La3+, one Pb2+, and one Si4+ atom. In the second Se2- site, Se2- is bonded in a 1-coordinate geometry to two La3+, one Pb2+, and one Si4+ atom. In the third Se2- site, Se2- is bonded in a 1-coordinate geometry to two La3+, one Pb2+, and one Si4+ atom. In the fourth Se2- site, Se2- is bonded in a distorted single-bond geometry to one La3+, two equivalent Pb2+, and one Si4+ atom. In the fifth Se2- site, Se2- is bonded in a 4-coordinate geometry to three La3+ and one Si4+ atom. In the sixth Se2- site, Se2- is bonded in a 3-coordinate geometry to two La3+, one Pb2+, and one Si4+ atom. In the seventh Se2- site, Se2- is bonded in a distorted T-shaped geometry to two equivalent La3+, one Pb2+, and one Si4+ atom. In the eighth Se2- site, Se2- is bonded in a 4-coordinate geometry to two equivalent La3+, one Pb2+, and one Si4+ atom.