Ta2Ni crystallizes in the hexagonal P6_3/mcm space group. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to six equivalent Ta(2) and six equivalent Ni(1) atoms to form distorted TaTa6Ni6 cuboctahedra that share corners with eighteen equivalent Ni(1)Ta9Ni3 cuboctahedra, edges with six equivalent Ta(1)Ta6Ni6 cuboctahedra, edges with twelve equivalent Ta(2)Ta8Ni4 cuboctahedra, faces with two equivalent Ta(1)Ta6Ni6 cuboctahedra, faces with six equivalent Ni(1)Ta9Ni3 cuboctahedra, and faces with twelve equivalent Ta(2)Ta8Ni4 cuboctahedra. In the second Ta site, Ta(2) is bonded to two equivalent Ta(1), six equivalent Ta(2), and four equivalent Ni(1) atoms to form distorted TaTa8Ni4 cuboctahedra that share corners with twelve equivalent Ta(2)Ta8Ni4 cuboctahedra, edges with four equivalent Ta(1)Ta6Ni6 cuboctahedra, edges with eight equivalent Ni(1)Ta9Ni3 cuboctahedra, edges with twelve equivalent Ta(2)Ta8Ni4 cuboctahedra, faces with four equivalent Ta(1)Ta6Ni6 cuboctahedra, faces with six equivalent Ta(2)Ta8Ni4 cuboctahedra, and faces with eight equivalent Ni(1)Ta9Ni3 cuboctahedra. Ni(1) is bonded to three equivalent Ta(1), six equivalent Ta(2), and three equivalent Ni(1) atoms to form distorted NiTa9Ni3 cuboctahedra that share corners with nine equivalent Ta(1)Ta6Ni6 cuboctahedra, corners with nine equivalent Ni(1)Ta9Ni3 cuboctahedra, edges with six equivalent Ni(1)Ta9Ni3 cuboctahedra, edges with twelve equivalent Ta(2)Ta8Ni4 cuboctahedra, faces with three equivalent Ta(1)Ta6Ni6 cuboctahedra, faces with five equivalent Ni(1)Ta9Ni3 cuboctahedra, and faces with twelve equivalent Ta(2)Ta8Ni4 cuboctahedra.
Ta2Ni crystallizes in the hexagonal P6_3/mcm space group. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to six equivalent Ta(2) and six equivalent Ni(1) atoms to form distorted TaTa6Ni6 cuboctahedra that share corners with eighteen equivalent Ni(1)Ta9Ni3 cuboctahedra, edges with six equivalent Ta(1)Ta6Ni6 cuboctahedra, edges with twelve equivalent Ta(2)Ta8Ni4 cuboctahedra, faces with two equivalent Ta(1)Ta6Ni6 cuboctahedra, faces with six equivalent Ni(1)Ta9Ni3 cuboctahedra, and faces with twelve equivalent Ta(2)Ta8Ni4 cuboctahedra. All Ta(1)-Ta(2) bond lengths are 2.89 Å. All Ta(1)-Ni(1) bond lengths are 2.83 Å. In the second Ta site, Ta(2) is bonded to two equivalent Ta(1), six equivalent Ta(2), and four equivalent Ni(1) atoms to form distorted TaTa8Ni4 cuboctahedra that share corners with twelve equivalent Ta(2)Ta8Ni4 cuboctahedra, edges with four equivalent Ta(1)Ta6Ni6 cuboctahedra, edges with eight equivalent Ni(1)Ta9Ni3 cuboctahedra, edges with twelve equivalent Ta(2)Ta8Ni4 cuboctahedra, faces with four equivalent Ta(1)Ta6Ni6 cuboctahedra, faces with six equivalent Ta(2)Ta8Ni4 cuboctahedra, and faces with eight equivalent Ni(1)Ta9Ni3 cuboctahedra. There are four shorter (2.78 Å) and two longer (2.92 Å) Ta(2)-Ta(2) bond lengths. All Ta(2)-Ni(1) bond lengths are 2.84 Å. Ni(1) is bonded to three equivalent Ta(1), six equivalent Ta(2), and three equivalent Ni(1) atoms to form distorted NiTa9Ni3 cuboctahedra that share corners with nine equivalent Ta(1)Ta6Ni6 cuboctahedra, corners with nine equivalent Ni(1)Ta9Ni3 cuboctahedra, edges with six equivalent Ni(1)Ta9Ni3 cuboctahedra, edges with twelve equivalent Ta(2)Ta8Ni4 cuboctahedra, faces with three equivalent Ta(1)Ta6Ni6 cuboctahedra, faces with five equivalent Ni(1)Ta9Ni3 cuboctahedra, and faces with twelve equivalent Ta(2)Ta8Ni4 cuboctahedra. All Ni(1)-Ni(1) bond lengths are 2.83 Å.