Materials Data on BaCaSi by Materials Project
BaCaSi crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Ba2+ is bonded to five equivalent Si4- atoms to form distorted BaSi5 trigonal bipyramids that share corners with eight equivalent CaSi4 tetrahedra, corners with eight equivalent BaSi5 trigonal bipyramids, edges with six equivalent CaSi4 tetrahedra, and edges with six equivalent BaSi5 trigonal bipyramids. There are a spread of Ba–Si bond distances ranging from 3.40–3.73 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 BaSi5 trigonal bipyramids, edges with two equivalent CaSi4 tetrahedra, and edges with six equivalent BaSi5 trigonal bipyramids. There are a spread of Ca–Si bond distances ranging from 3.10–3.15 Å. Si4- is bonded in a 9-coordinate geometry to five equivalent Ba2+ and four equivalent Ca2+ atoms.