Materials Data on Ca(Al10Cr)2 by Materials Project

Abstract

Ca(CrAl10)2 crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. Ca is bonded in a 4-coordinate geometry to sixteen Al atoms. There are four shorter (3.13 Å) and twelve longer (3.20 Å) Ca–Al bond lengths. Cr is bonded to twelve Al atoms to form CrAl12 cuboctahedra that share corners with six equivalent CrAl12 cuboctahedra, edges with eighteen equivalent AlCaAl10Cr cuboctahedra, and faces with six equivalent AlCaAl10Cr cuboctahedra. There are six shorter (2.56 Å) and six longer (2.79 Å) Cr–Al bond lengths. There are three inequivalent Al sites. In the first Al site, Al is bonded in a 12-coordinate geometry to two equivalent Cr and ten Al atoms. There are a spread of Al–Al bond distances ranging from 2.70–2.83 Å. In the second Al site, Al is bonded in a linear geometry to two equivalent Ca and twelve equivalent Al atoms. All Al–Al bond lengths are 3.09 Å. In the third Al site, Al is bonded to one Ca, one Cr, and ten Al atoms to form distorted AlCaAl10Cr cuboctahedra that share corners with fifteen equivalent AlCaAl10Cr cuboctahedra, edges with two equivalent AlCaAl10Cr cuboctahedra, edges with three equivalent CrAl12 cuboctahedra, a faceface with one CrAl12 cuboctahedra, and faces with fifteen equivalent AlCaAl10Cr cuboctahedra. There are a spread of Al–Al bond distances ranging from 2.70–2.90 Å.