Materials Data on Sr3CaS4 by Materials Project
Sr3CaS4 is Caswellsilverite-like structured and crystallizes in the orthorhombic Cmmm space group. The structure is three-dimensional. there are two inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded to six S2- atoms to form SrS6 octahedra that share corners with six equivalent SrS6 octahedra, edges with four equivalent CaS6 octahedra, and edges with eight SrS6 octahedra. The corner-sharing octahedra tilt angles range from 2–3°. All Sr–S bond lengths are 2.99 Å. In the second Sr2+ site, Sr2+ is bonded to six S2- atoms to form SrS6 octahedra that share corners with six equivalent CaS6 octahedra, edges with two equivalent CaS6 octahedra, and edges with ten SrS6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. All Sr–S bond lengths are 3.05 Å. Ca2+ is bonded to six S2- atoms to form CaS6 octahedra that share corners with six equivalent SrS6 octahedra, edges with two equivalent CaS6 octahedra, and edges with ten SrS6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. All Ca–S bond lengths are 2.94 Å. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded to five Sr2+ and one Ca2+ atom to form a mixture of edge and corner-sharing SSr5Ca octahedra. The corner-sharing octahedral tilt angles are 0°. In the second S2- site, S2- is bonded to four Sr2+ and two equivalent Ca2+ atoms to form SSr4Ca2 octahedra that share corners with six equivalent SSr4Ca2 octahedra and edges with twelve SSr5Ca octahedra. The corner-sharing octahedral tilt angles are 0°.