Materials Data on AlCr3B4 by Materials Project
Cr3AlB4 crystallizes in the orthorhombic Pmmm space group. The structure is three-dimensional. there are two inequivalent Cr3+ sites. In the first Cr3+ site, Cr3+ is bonded in a 6-coordinate geometry to six B3- atoms. There are two shorter (2.13 Å) and four longer (2.17 Å) Cr–B bond lengths. In the second Cr3+ site, Cr3+ is bonded to twelve B3- atoms to form a mixture of edge and face-sharing CrB12 cuboctahedra. There are eight shorter (2.26 Å) and four longer (2.33 Å) Cr–B bond lengths. Al3+ is bonded in a linear geometry to two equivalent B3- atoms. Both Al–B bond lengths are 2.24 Å. There are two inequivalent B3- sites. In the first B3- site, B3- is bonded in a 9-coordinate geometry to six Cr3+ and three B3- atoms. All B–B bond lengths are 1.74 Å. In the second B3- site, B3- is bonded in a 9-coordinate geometry to six Cr3+, one Al3+, and two equivalent B3- atoms.