Materials Data on Th(Al2Cr)4 by Materials Project

Abstract

ThCr4Al8 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Th is bonded in a 12-coordinate geometry to eight equivalent Cr and twelve Al atoms. All Th–Cr bond lengths are 3.43 Å. There are four shorter (3.11 Å) and eight longer (3.22 Å) Th–Al bond lengths. Cr is bonded to two equivalent Th, two equivalent Cr, and eight Al atoms to form distorted CrTh2Al8Cr2 cuboctahedra that share corners with eight equivalent AlTh2Al6Cr4 cuboctahedra, corners with ten equivalent CrTh2Al8Cr2 cuboctahedra, edges with four equivalent CrTh2Al8Cr2 cuboctahedra, edges with four equivalent AlTh2Al6Cr4 cuboctahedra, faces with six equivalent CrTh2Al8Cr2 cuboctahedra, and faces with eight equivalent AlTh2Al6Cr4 cuboctahedra. Both Cr–Cr bond lengths are 2.51 Å. There are four shorter (2.59 Å) and four longer (2.72 Å) Cr–Al bond lengths. There are two inequivalent Al sites. In the first Al site, Al is bonded to two equivalent Th, four equivalent Cr, and six Al atoms to form distorted AlTh2Al6Cr4 cuboctahedra that share corners with eight equivalent CrTh2Al8Cr2 cuboctahedra, corners with ten equivalent AlTh2Al6Cr4 cuboctahedra, edges with three equivalent AlTh2Al6Cr4 cuboctahedra, edges with four equivalent CrTh2Al8Cr2 cuboctahedra, faces with seven equivalent AlTh2Al6Cr4 cuboctahedra, and faces with eight equivalent CrTh2Al8Cr2 cuboctahedra. There are two shorter (2.74 Å) and four longer (2.86 Å) Al–Al bond lengths. In the second Al site, Al is bonded in a 10-coordinate geometry to one Th, four equivalent Cr, and five Al atoms. The Al–Al bond length is 2.80 Å.