Materials Data on Ta3AlB8 by Materials Project

Abstract

Ta3AlB8 is hexagonal omega structure-derived structured and crystallizes in the hexagonal P6/mmm space group. The structure is three-dimensional. there are two inequivalent Ta3+ sites. In the first Ta3+ site, Ta3+ is bonded to twelve B+1.50- atoms to form TaB12 cuboctahedra that share edges with six equivalent TaB12 cuboctahedra, edges with six equivalent AlB12 cuboctahedra, a faceface with one AlB12 cuboctahedra, and faces with seven TaB12 cuboctahedra. There are six shorter (2.41 Å) and six longer (2.53 Å) Ta–B bond lengths. In the second Ta3+ site, Ta3+ is bonded to twelve equivalent B+1.50- atoms to form a mixture of edge and face-sharing TaB12 cuboctahedra. All Ta–B bond lengths are 2.44 Å. Al3+ is bonded to twelve equivalent B+1.50- atoms to form AlB12 cuboctahedra that share edges with twelve equivalent TaB12 cuboctahedra, faces with two equivalent TaB12 cuboctahedra, and faces with six equivalent AlB12 cuboctahedra. All Al–B bond lengths are 2.41 Å. There are two inequivalent B+1.50- sites. In the first B+1.50- site, B+1.50- is bonded in a 9-coordinate geometry to three equivalent Ta3+, three equivalent Al3+, and three equivalent B+1.50- atoms. All B–B bond lengths are 1.77 Å. In the second B+1.50- site, B+1.50- is bonded in a 9-coordinate geometry to six Ta3+ and three equivalent B+1.50- atoms. All B–B bond lengths are 1.77 Å.