LuTa3 crystallizes in the hexagonal P6_3/mmc space group. Lu(1) is bonded to twelve Ta(1,1,1) atoms to form LuTa12 cuboctahedra that share corners with six equivalent Lu(1)Ta12 cuboctahedra; corners with twelve Ta(1,1)Lu4Ta8 cuboctahedra; edges with eighteen Ta(1,1,1)Lu4Ta8 cuboctahedra; faces with eight equivalent Lu(1)Ta12 cuboctahedra; and faces with twelve Ta(1,1,1)Lu4Ta8 cuboctahedra. There are three inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to four equivalent Lu(1) and eight Ta(1,1) atoms to form distorted TaLu4Ta8 cuboctahedra that share corners with four equivalent Lu(1)Ta12 cuboctahedra; corners with fourteen Ta(1,1)Lu4Ta8 cuboctahedra; edges with six equivalent Lu(1)Ta12 cuboctahedra; edges with twelve Ta(1,1)Lu4Ta8 cuboctahedra; faces with four equivalent Lu(1)Ta12 cuboctahedra; and faces with sixteen Ta(1,1,1)Lu4Ta8 cuboctahedra. In the second Ta site, Ta(1) is bonded to four equivalent Lu(1) and eight Ta(1,1,1) atoms to form distorted TaLu4Ta8 cuboctahedra that share corners with four equivalent Lu(1)Ta12 cuboctahedra; corners with fourteen Ta(1,1)Lu4Ta8 cuboctahedra; edges with six equivalent Lu(1)Ta12 cuboctahedra; edges with twelve Ta(1,1,1)Lu4Ta8 cuboctahedra; faces with four equivalent Lu(1)Ta12 cuboctahedra; and faces with sixteen Ta(1,1,1)Lu4Ta8 cuboctahedra. In the third Ta site, Ta(1) is bonded to four equivalent Lu(1) and eight Ta(1,1) atoms to form distorted TaLu4Ta8 cuboctahedra that share corners with four equivalent Lu(1)Ta12 cuboctahedra; corners with fourteen Ta(1,1)Lu4Ta8 cuboctahedra; edges with six equivalent Lu(1)Ta12 cuboctahedra; edges with twelve Ta(1,1)Lu4Ta8 cuboctahedra; faces with four equivalent Lu(1)Ta12 cuboctahedra; and faces with sixteen Ta(1,1,1)Lu4Ta8 cuboctahedra.
LuTa3 crystallizes in the hexagonal P6_3/mmc space group. Lu(1) is bonded to twelve Ta(1,1,1) atoms to form LuTa12 cuboctahedra that share corners with six equivalent Lu(1)Ta12 cuboctahedra; corners with twelve Ta(1,1)Lu4Ta8 cuboctahedra; edges with eighteen Ta(1,1,1)Lu4Ta8 cuboctahedra; faces with eight equivalent Lu(1)Ta12 cuboctahedra; and faces with twelve Ta(1,1,1)Lu4Ta8 cuboctahedra. There are six shorter (3.13 Å) and six longer (3.19 Å) Lu(1)-Ta(1,1,1) bond lengths. There are three inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to four equivalent Lu(1) and eight Ta(1,1) atoms to form distorted TaLu4Ta8 cuboctahedra that share corners with four equivalent Lu(1)Ta12 cuboctahedra; corners with fourteen Ta(1,1)Lu4Ta8 cuboctahedra; edges with six equivalent Lu(1)Ta12 cuboctahedra; edges with twelve Ta(1,1)Lu4Ta8 cuboctahedra; faces with four equivalent Lu(1)Ta12 cuboctahedra; and faces with sixteen Ta(1,1,1)Lu4Ta8 cuboctahedra. There are a spread of Ta(1)-Ta(1,1) bond distances ranging from 2.80-3.44 Å. In the second Ta site, Ta(1) is bonded to four equivalent Lu(1) and eight Ta(1,1,1) atoms to form distorted TaLu4Ta8 cuboctahedra that share corners with four equivalent Lu(1)Ta12 cuboctahedra; corners with fourteen Ta(1,1)Lu4Ta8 cuboctahedra; edges with six equivalent Lu(1)Ta12 cuboctahedra; edges with twelve Ta(1,1,1)Lu4Ta8 cuboctahedra; faces with four equivalent Lu(1)Ta12 cuboctahedra; and faces with sixteen Ta(1,1,1)Lu4Ta8 cuboctahedra. All Ta(1)-Ta(1,1) bond lengths are 2.97 Å. In the third Ta site, Ta(1) is bonded to four equivalent Lu(1) and eight Ta(1,1) atoms to form distorted TaLu4Ta8 cuboctahedra that share corners with four equivalent Lu(1)Ta12 cuboctahedra; corners with fourteen Ta(1,1)Lu4Ta8 cuboctahedra; edges with six equivalent Lu(1)Ta12 cuboctahedra; edges with twelve Ta(1,1)Lu4Ta8 cuboctahedra; faces with four equivalent Lu(1)Ta12 cuboctahedra; and faces with sixteen Ta(1,1,1)Lu4Ta8 cuboctahedra. Both Ta(1)-Ta(1) bond lengths are 2.97 Å.