Materials Data on CaMgSi by Materials Project

Abstract

CaMgSi crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Ca2+ is bonded to five equivalent Si4- atoms to form distorted CaSi5 trigonal bipyramids that share corners with eight equivalent MgSi4 tetrahedra, corners with eight equivalent CaSi5 trigonal bipyramids, edges with six equivalent MgSi4 tetrahedra, and edges with six equivalent CaSi5 trigonal bipyramids. There are a spread of Ca–Si bond distances ranging from 3.09–3.20 Å. Mg2+ is bonded to four equivalent Si4- atoms to form MgSi4 tetrahedra that share corners with eight equivalent MgSi4 tetrahedra, corners with eight equivalent CaSi5 trigonal bipyramids, edges with two equivalent MgSi4 tetrahedra, and edges with six equivalent CaSi5 trigonal bipyramids. There are two shorter (2.75 Å) and two longer (2.83 Å) Mg–Si bond lengths. Si4- is bonded in a 9-coordinate geometry to five equivalent Ca2+ and four equivalent Mg2+ atoms.