Materials Data on SrCaSi4 by Materials Project

Abstract

SrCaSi4 is Caswellsilverite-like structured and crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. Sr is bonded to six equivalent Si atoms to form distorted SrSi6 octahedra that share corners with six equivalent SiCa3Si3 octahedra, edges with six equivalent SrSi6 octahedra, and edges with six equivalent SiCa3Si3 octahedra. The corner-sharing octahedral tilt angles are 23°. All Sr–Si bond lengths are 3.14 Å. Ca is bonded to six equivalent Si atoms to form edge-sharing CaSi6 octahedra. All Ca–Si bond lengths are 3.06 Å. There are two inequivalent Si sites. In the first Si site, Si is bonded in a 6-coordinate geometry to three equivalent Sr and three equivalent Si atoms. All Si–Si bond lengths are 2.43 Å. In the second Si site, Si is bonded to three equivalent Ca and three equivalent Si atoms to form distorted SiCa3Si3 octahedra that share corners with three equivalent SrSi6 octahedra, corners with three equivalent SiCa3Si3 octahedra, edges with three equivalent SrSi6 octahedra, and edges with nine equivalent SiCa3Si3 octahedra. The corner-sharing octahedra tilt angles range from 0–23°.