Materials Data on Ca(AlS2)2 by Materials Project
CaAl2S4 crystallizes in the orthorhombic Fddd space group. The structure is three-dimensional. there are three inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are six shorter (3.03 Å) and two longer (3.07 Å) Ca–S bond lengths. In the second Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are four shorter (3.03 Å) and four longer (3.06 Å) Ca–S bond lengths. In the third Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are four shorter (3.03 Å) and four longer (3.05 Å) Ca–S bond lengths. There are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four S2- atoms to form a mixture of edge and corner-sharing AlS4 tetrahedra. There are one shorter (2.25 Å) and three longer (2.28 Å) Al–S bond lengths. In the second Al3+ site, Al3+ is bonded to four S2- atoms to form a mixture of edge and corner-sharing AlS4 tetrahedra. There are a spread of Al–S bond distances ranging from 2.25–2.28 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded in a 4-coordinate geometry to two Ca2+ and two Al3+ atoms. In the second S2- site, S2- is bonded in a 4-coordinate geometry to two Ca2+ and two equivalent Al3+ atoms. In the third S2- site, S2- is bonded in a 4-coordinate geometry to two Ca2+ and two equivalent Al3+ atoms. In the fourth S2- site, S2- is bonded in a 4-coordinate geometry to two Ca2+ and two Al3+ atoms.