Materials Data on Ba3(AlGe)2 by Materials Project

Abstract

Ba3Al2Ge2 crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. there are two inequivalent Ba sites. In the first Ba site, Ba is bonded in a 7-coordinate geometry to two equivalent Al and five equivalent Ge atoms. Both Ba–Al bond lengths are 3.53 Å. There are four shorter (3.52 Å) and one longer (3.67 Å) Ba–Ge bond lengths. In the second Ba site, Ba is bonded to eight equivalent Al and four equivalent Ge atoms to form a mixture of edge and face-sharing BaAl8Ge4 cuboctahedra. All Ba–Al bond lengths are 3.62 Å. All Ba–Ge bond lengths are 3.76 Å. Al is bonded in a 2-coordinate geometry to six Ba, one Al, and two equivalent Ge atoms. The Al–Al bond length is 2.61 Å. Both Al–Ge bond lengths are 2.61 Å. Ge is bonded in a 2-coordinate geometry to seven Ba and two equivalent Al atoms.