DOI: 10.17188/1204590
title: Materials Data on Ca4Al51Cr7 by Materials Project

description: Ca4Cr7Al51 is Bergman Structure: Mg32(Al,Zn)49 Bergman-like structured and crystallizes in the trigonal P3m1 space group. The structure is three-dimensional. there are four inequivalent Ca sites. In the first Ca site, Ca is bonded in a 9-coordinate geometry to fifteen Al atoms. There are a spread of Ca–Al bond distances ranging from 3.14–3.44 Å. In the second Ca site, Ca is bonded in a 3-coordinate geometry to fifteen Al atoms. There are a spread of Ca–Al bond distances ranging from 3.15–3.23 Å. In the third Ca site, Ca is bonded in a 9-coordinate geometry to fifteen Al atoms. There are a spread of Ca–Al bond distances ranging from 3.14–3.41 Å. In the fourth Ca site, Ca is bonded in a 3-coordinate geometry to fifteen Al atoms. There are a spread of Ca–Al bond distances ranging from 3.15–3.23 Å. There are three inequivalent Cr sites. In the first Cr site, Cr is bonded to twelve Al atoms to form CrAl12 cuboctahedra that share edges with six AlCaAl10Cr cuboctahedra and faces with six AlCaAl10Cr cuboctahedra. There are six shorter (2.54 Å) and six longer (2.78 Å) Cr–Al bond lengths. In the second Cr site, Cr is bonded in a 10-coordinate geometry to ten Al atoms. There are a spread of Cr–Al bond distances ranging from 2.41–2.66 Å. In the third Cr site, Cr is bonded in a 10-coordinate geometry to ten Al atoms. There are a spread of Cr–Al bond distances ranging from 2.41–2.67 Å. There are fourteen inequivalent Al sites. In the first Al site, Al is bonded in a 11-coordinate geometry to one Ca, two equivalent Cr, and eight Al atoms. There are a spread of Al–Al bond distances ranging from 2.65–2.83 Å. In the second Al site, Al is bonded in a 2-coordinate geometry to two Cr and ten Al atoms. There are a spread of Al–Al bond distances ranging from 2.70–3.02 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 five AlCaAl10Cr cuboctahedra, edges with two equivalent AlCaAl10Cr cuboctahedra, a faceface with one CrAl12 cuboctahedra, and faces with nine AlCaAl10Cr cuboctahedra. There are a spread of Al–Al bond distances ranging from 2.66–3.11 Å. In the fourth Al site, Al is bonded to one Ca, one Cr, and ten Al atoms to form distorted AlCaAl10Cr cuboctahedra that share corners with six AlCaAl10Cr cuboctahedra, an edgeedge with one CrAl12 cuboctahedra, and faces with seven AlCaAl10Cr cuboctahedra. There are a spread of Al–Al bond distances ranging from 2.66–3.05 Å. In the fifth 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 2.70–3.03 Å. In the sixth Al site, Al is bonded to one Ca, one Cr, and ten Al atoms to form distorted AlCaAl10Cr cuboctahedra that share corners with five AlCaAl10Cr cuboctahedra, edges with two equivalent AlCaAl10Cr cuboctahedra, a faceface with one CrAl12 cuboctahedra, and faces with nine AlCaAl10Cr cuboctahedra. There are four shorter (2.79 Å) and two longer (3.11 Å) Al–Al bond lengths. In the seventh Al site, Al is bonded to one Ca, one Cr, and ten Al atoms to form distorted AlCaAl10Cr cuboctahedra that share corners with six AlCaAl10Cr cuboctahedra, an edgeedge with one CrAl12 cuboctahedra, and faces with seven AlCaAl10Cr cuboctahedra. There are a spread of Al–Al bond distances ranging from 2.70–3.04 Å. In the eighth Al site, Al is bonded in a 11-coordinate geometry to one Ca, two equivalent Cr, and eight Al atoms. There are a spread of Al–Al bond distances ranging from 2.65–2.73 Å. In the ninth Al site, Al is bonded in a distorted linear geometry to two Ca and eight Al atoms. In the tenth Al site, Al is bonded in a 2-coordinate geometry to two Cr and eight Al atoms. Both Al–Al bond lengths are 2.85 Å. In the eleventh 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 2.69–2.88 Å. In the twelfth Al site, Al is bonded in a 11-coordinate geometry to two Ca, two Cr, and seven Al atoms. There are a spread of Al–Al bond distances ranging from 2.88–2.99 Å. In the thirteenth Al site, Al is bonded in a 11-coordinate geometry to two Ca, one Cr, and eight Al atoms. There are one shorter (2.68 Å) and one longer (2.78 Å) Al–Al bond lengths. In the fourteenth Al site, Al is bonded in a 11-coordinate geometry to two Ca, one Cr, and eight Al atoms. There are one shorter (2.69 Å) and one longer (2.78 Å) Al–Al bond lengths.