Materials Data on Ta3Cu by Materials Project
Ta3Cu is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are two inequivalent Ta sites. In the first Ta site, Ta is bonded to eight Ta and four equivalent Cu atoms to form distorted TaTa8Cu4 cuboctahedra that share corners with twelve equivalent TaTa8Cu4 cuboctahedra, edges with eight equivalent CuTa12 cuboctahedra, edges with sixteen TaTa8Cu4 cuboctahedra, faces with four equivalent CuTa12 cuboctahedra, and faces with fourteen TaTa8Cu4 cuboctahedra. There are four shorter (2.84 Å) and four longer (2.91 Å) Ta–Ta bond lengths. All Ta–Cu bond lengths are 2.91 Å. In the second Ta site, Ta is bonded to eight equivalent Ta and four equivalent Cu atoms to form distorted TaTa8Cu4 cuboctahedra that share corners with four equivalent TaTa8Cu4 cuboctahedra, corners with eight equivalent CuTa12 cuboctahedra, edges with twenty-four TaTa8Cu4 cuboctahedra, faces with six equivalent CuTa12 cuboctahedra, and faces with twelve TaTa8Cu4 cuboctahedra. All Ta–Cu bond lengths are 2.84 Å. Cu is bonded to twelve Ta atoms to form CuTa12 cuboctahedra that share corners with four equivalent CuTa12 cuboctahedra, corners with eight equivalent TaTa8Cu4 cuboctahedra, edges with eight equivalent CuTa12 cuboctahedra, edges with sixteen equivalent TaTa8Cu4 cuboctahedra, faces with four equivalent CuTa12 cuboctahedra, and faces with fourteen TaTa8Cu4 cuboctahedra.