Materials Data on SrCaSi by Materials Project
SrCaSi crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Sr2+ is bonded to five equivalent Si4- atoms to form distorted SrSi5 trigonal bipyramids that share corners with eight equivalent CaSi4 tetrahedra, corners with eight equivalent SrSi5 trigonal bipyramids, edges with six equivalent CaSi4 tetrahedra, and edges with six equivalent SrSi5 trigonal bipyramids. There are a spread of Sr–Si bond distances ranging from 3.28–3.59 Å. Ca2+ is bonded to four equivalent Si4- atoms to form CaSi4 tetrahedra that share corners with eight equivalent CaSi4 tetrahedra, corners with eight equivalent SrSi5 trigonal bipyramids, edges with two equivalent CaSi4 tetrahedra, and edges with six equivalent SrSi5 trigonal bipyramids. There are a spread of Ca–Si bond distances ranging from 3.04–3.09 Å. Si4- is bonded in a 9-coordinate geometry to five equivalent Sr2+ and four equivalent Ca2+ atoms.