Materials Data on Ca3(AlSi)2 by Materials Project

Abstract

Ca3(AlSi)2 crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. there are two inequivalent Ca sites. In the first Ca site, Ca is bonded to eight equivalent Al and four equivalent Si atoms to form a mixture of distorted edge and face-sharing CaAl8Si4 cuboctahedra. All Ca–Al bond lengths are 3.31 Å. All Ca–Si bond lengths are 3.51 Å. In the second Ca site, Ca is bonded in a 7-coordinate geometry to two equivalent Al and five equivalent Si atoms. Both Ca–Al bond lengths are 3.15 Å. There are one shorter (3.14 Å) and four longer (3.15 Å) Ca–Si bond lengths. Al is bonded in a 2-coordinate geometry to six Ca, one Al, and two equivalent Si atoms. The Al–Al bond length is 2.55 Å. Both Al–Si bond lengths are 2.48 Å. Si is bonded in a 7-coordinate geometry to seven Ca and two equivalent Al atoms.