Materials Data on Ca2SiS4 by Materials Project

Ca2SiS4 is Spinel-like structured and crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to six S2- atoms to form CaS6 octahedra that share corners with four equivalent CaS6 octahedra, corners with two equivalent SiS4 tetrahedra, edges with four CaS6 octahedra, and edges with two equivalent SiS4 tetrahedra. The corner-sharing octahedra tilt angles range from 58–65°. There are a spread of Ca–S bond distances ranging from 2.78–2.89 Å. In the second Ca2+ site, Ca2+ is bonded to six S2- atoms to form CaS6 octahedra that share corners with eight CaS6 octahedra, corners with four equivalent SiS4 tetrahedra, edges with two equivalent CaS6 octahedra, and an edgeedge with one SiS4 tetrahedra. The corner-sharing octahedra tilt angles range from 51–65°. There are a spread of Ca–S bond distances ranging from 2.81–2.89 Å. Si4+ is bonded to four S2- atoms to form SiS4 tetrahedra that share corners with six CaS6 octahedra and edges with three CaS6 octahedra. The corner-sharing octahedra tilt angles range from 52–57°. There are a spread of Si–S bond distances ranging from 2.12–2.16 Å. There are three inequivalent S2- sites. In the first S2- site, S2- is bonded in a rectangular see-saw-like geometry to three Ca2+ and one Si4+ atom. In the second S2- site, S2- is bonded to three Ca2+ and one Si4+ atom to form distorted corner-sharing SCa3Si trigonal pyramids. In the third S2- site, S2- is bonded in a rectangular see-saw-like geometry to three Ca2+ and one Si4+ atom.