Ni3Ta is beta Cu3Ti-like structured and crystallizes in the monoclinic P2_1/m space group. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one Ni(3), two equivalent Ni(1), three equivalent Ni(4), and six equivalent Ni(2) atoms to form TaNi12 cuboctahedra that share  a cornercorner with one Ta(2)Ni12 cuboctahedra, corners with two equivalent Ta(1)Ni12 cuboctahedra, corners with four equivalent Ni(1)Ta4Ni8 cuboctahedra, corners with four equivalent Ni(3)Ta4Ni8 cuboctahedra, corners with four equivalent Ni(4)Ta4Ni8 cuboctahedra, edges with three equivalent Ta(2)Ni12 cuboctahedra, edges with four equivalent Ta(1)Ni12 cuboctahedra, edges with six equivalent Ni(1)Ta4Ni8 cuboctahedra, edges with eight equivalent Ni(2)Ta4Ni8 cuboctahedra, faces with two equivalent Ta(1)Ni12 cuboctahedra, faces with two equivalent Ni(1)Ta4Ni8 cuboctahedra, faces with two equivalent Ni(3)Ta4Ni8 cuboctahedra, faces with three equivalent Ta(2)Ni12 cuboctahedra, faces with four equivalent Ni(4)Ta4Ni8 cuboctahedra, and faces with six equivalent Ni(2)Ta4Ni8 cuboctahedra. In the second Ta site, Ta(2) is bonded to one Ni(4), two equivalent Ni(2), three equivalent Ni(3), and six equivalent Ni(1) atoms to form TaNi12 cuboctahedra that share  a cornercorner with one Ta(1)Ni12 cuboctahedra, corners with two equivalent Ta(2)Ni12 cuboctahedra, corners with four equivalent Ni(2)Ta4Ni8 cuboctahedra, corners with four equivalent Ni(3)Ta4Ni8 cuboctahedra, corners with four equivalent Ni(4)Ta4Ni8 cuboctahedra, edges with three equivalent Ta(1)Ni12 cuboctahedra, edges with four equivalent Ta(2)Ni12 cuboctahedra, edges with six equivalent Ni(2)Ta4Ni8 cuboctahedra, edges with eight equivalent Ni(1)Ta4Ni8 cuboctahedra, faces with two equivalent Ta(2)Ni12 cuboctahedra, faces with two equivalent Ni(2)Ta4Ni8 cuboctahedra, faces with two equivalent Ni(4)Ta4Ni8 cuboctahedra, faces with three equivalent Ta(1)Ni12 cuboctahedra, faces with four equivalent Ni(3)Ta4Ni8 cuboctahedra, and faces with six equivalent Ni(1)Ta4Ni8 cuboctahedra. There are four inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one Ta(1), three equivalent Ta(2), one Ni(2), one Ni(4), three equivalent Ni(1), and three equivalent Ni(3) atoms to form distorted NiTa4Ni8 cuboctahedra that share corners with two equivalent Ta(1)Ni12 cuboctahedra, corners with two equivalent Ni(4)Ta4Ni8 cuboctahedra, corners with five equivalent Ni(2)Ta4Ni8 cuboctahedra, corners with six equivalent Ni(1)Ta4Ni8 cuboctahedra, edges with three equivalent Ta(1)Ni12 cuboctahedra, edges with three equivalent Ni(2)Ta4Ni8 cuboctahedra, edges with three equivalent Ni(4)Ta4Ni8 cuboctahedra, edges with four equivalent Ta(2)Ni12 cuboctahedra, edges with four equivalent Ni(1)Ta4Ni8 cuboctahedra, edges with four equivalent Ni(3)Ta4Ni8 cuboctahedra,  a faceface with one Ta(1)Ni12 cuboctahedra,  a faceface with one Ni(4)Ta4Ni8 cuboctahedra, faces with three equivalent Ta(2)Ni12 cuboctahedra, faces with three equivalent Ni(3)Ta4Ni8 cuboctahedra, faces with five equivalent Ni(2)Ta4Ni8 cuboctahedra, and faces with six equivalent Ni(1)Ta4Ni8 cuboctahedra. In the second Ni site, Ni(2) is bonded to one Ta(2), three equivalent Ta(1), one Ni(1), one Ni(3), three equivalent Ni(2), and three equivalent Ni(4) atoms to form distorted NiTa4Ni8 cuboctahedra that share corners with two equivalent Ta(2)Ni12 cuboctahedra, corners with two equivalent Ni(3)Ta4Ni8 cuboctahedra, corners with five equivalent Ni(1)Ta4Ni8 cuboctahedra, corners with six equivalent Ni(2)Ta4Ni8 cuboctahedra, edges with three equivalent Ta(2)Ni12 cuboctahedra, edges with three equivalent Ni(1)Ta4Ni8 cuboctahedra, edges with three equivalent Ni(3)Ta4Ni8 cuboctahedra, edges with four equivalent Ta(1)Ni12 cuboctahedra, edges with four equivalent Ni(2)Ta4Ni8 cuboctahedra, edges with four equivalent Ni(4)Ta4Ni8 cuboctahedra,  a faceface with one Ta(2)Ni12 cuboctahedra,  a faceface with one Ni(3)Ta4Ni8 cuboctahedra, faces with three equivalent Ta(1)Ni12 cuboctahedra, faces with three equivalent Ni(4)Ta4Ni8 cuboctahedra, faces with five equivalent Ni(1)Ta4Ni8 cuboctahedra, and faces with six equivalent Ni(2)Ta4Ni8 cuboctahedra. In the third Ni site, Ni(3) is bonded to one Ta(1), three equivalent Ta(2), two equivalent Ni(2), and six equivalent Ni(1) atoms to form distorted NiTa4Ni8 cuboctahedra that share  a cornercorner with one Ni(4)Ta4Ni8 cuboctahedra, corners with two equivalent Ni(3)Ta4Ni8 cuboctahedra, corners with four equivalent Ta(1)Ni12 cuboctahedra, corners with four equivalent Ta(2)Ni12 cuboctahedra, corners with four equivalent Ni(2)Ta4Ni8 cuboctahedra, edges with three equivalent Ni(4)Ta4Ni8 cuboctahedra, edges with four equivalent Ni(3)Ta4Ni8 cuboctahedra, edges with six equivalent Ni(2)Ta4Ni8 cuboctahedra, edges with eight equivalent Ni(1)Ta4Ni8 cuboctahedra, faces with two equivalent Ta(1)Ni12 cuboctahedra, faces with two equivalent Ni(2)Ta4Ni8 cuboctahedra, faces with two equivalent Ni(3)Ta4Ni8 cuboctahedra, faces with three equivalent Ni(4)Ta4Ni8 cuboctahedra, faces with four equivalent Ta(2)Ni12 cuboctahedra, and faces with six equivalent Ni(1)Ta4Ni8 cuboctahedra. In the fourth Ni site, Ni(4) is bonded to one Ta(2), three equivalent Ta(1), two equivalent Ni(1), and six equivalent Ni(2) atoms to form distorted NiTa4Ni8 cuboctahedra that share  a cornercorner with one Ni(3)Ta4Ni8 cuboctahedra, corners with two equivalent Ni(4)Ta4Ni8 cuboctahedra, corners with four equivalent Ta(1)Ni12 cuboctahedra, corners with four equivalent Ta(2)Ni12 cuboctahedra, corners with four equivalent Ni(1)Ta4Ni8 cuboctahedra, edges with three equivalent Ni(3)Ta4Ni8 cuboctahedra, edges with four equivalent Ni(4)Ta4Ni8 cuboctahedra, edges with six equivalent Ni(1)Ta4Ni8 cuboctahedra, edges with eight equivalent Ni(2)Ta4Ni8 cuboctahedra, faces with two equivalent Ta(2)Ni12 cuboctahedra, faces with two equivalent Ni(1)Ta4Ni8 cuboctahedra, faces with two equivalent Ni(4)Ta4Ni8 cuboctahedra, faces with three equivalent Ni(3)Ta4Ni8 cuboctahedra, faces with four equivalent Ta(1)Ni12 cuboctahedra, and faces with six equivalent Ni(2)Ta4Ni8 cuboctahedra.
Ni3Ta is beta Cu3Ti-like structured and crystallizes in the monoclinic P2_1/m space group. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one Ni(3), two equivalent Ni(1), three equivalent Ni(4), and six equivalent Ni(2) atoms to form TaNi12 cuboctahedra that share  a cornercorner with one Ta(2)Ni12 cuboctahedra, corners with two equivalent Ta(1)Ni12 cuboctahedra, corners with four equivalent Ni(1)Ta4Ni8 cuboctahedra, corners with four equivalent Ni(3)Ta4Ni8 cuboctahedra, corners with four equivalent Ni(4)Ta4Ni8 cuboctahedra, edges with three equivalent Ta(2)Ni12 cuboctahedra, edges with four equivalent Ta(1)Ni12 cuboctahedra, edges with six equivalent Ni(1)Ta4Ni8 cuboctahedra, edges with eight equivalent Ni(2)Ta4Ni8 cuboctahedra, faces with two equivalent Ta(1)Ni12 cuboctahedra, faces with two equivalent Ni(1)Ta4Ni8 cuboctahedra, faces with two equivalent Ni(3)Ta4Ni8 cuboctahedra, faces with three equivalent Ta(2)Ni12 cuboctahedra, faces with four equivalent Ni(4)Ta4Ni8 cuboctahedra, and faces with six equivalent Ni(2)Ta4Ni8 cuboctahedra. The Ta(1)-Ni(3) bond length is 2.56 Å. Both Ta(1)-Ni(1) bond lengths are 2.62 Å. There are two shorter (2.54 Å) and one longer (2.56 Å) Ta(1)-Ni(4) bond length. There are two shorter (2.56 Å) and four longer (2.59 Å) Ta(1)-Ni(2) bond lengths. In the second Ta site, Ta(2) is bonded to one Ni(4), two equivalent Ni(2), three equivalent Ni(3), and six equivalent Ni(1) atoms to form TaNi12 cuboctahedra that share  a cornercorner with one Ta(1)Ni12 cuboctahedra, corners with two equivalent Ta(2)Ni12 cuboctahedra, corners with four equivalent Ni(2)Ta4Ni8 cuboctahedra, corners with four equivalent Ni(3)Ta4Ni8 cuboctahedra, corners with four equivalent Ni(4)Ta4Ni8 cuboctahedra, edges with three equivalent Ta(1)Ni12 cuboctahedra, edges with four equivalent Ta(2)Ni12 cuboctahedra, edges with six equivalent Ni(2)Ta4Ni8 cuboctahedra, edges with eight equivalent Ni(1)Ta4Ni8 cuboctahedra, faces with two equivalent Ta(2)Ni12 cuboctahedra, faces with two equivalent Ni(2)Ta4Ni8 cuboctahedra, faces with two equivalent Ni(4)Ta4Ni8 cuboctahedra, faces with three equivalent Ta(1)Ni12 cuboctahedra, faces with four equivalent Ni(3)Ta4Ni8 cuboctahedra, and faces with six equivalent Ni(1)Ta4Ni8 cuboctahedra. The Ta(2)-Ni(4) bond length is 2.58 Å. Both Ta(2)-Ni(2) bond lengths are 2.57 Å. There are two shorter (2.54 Å) and one longer (2.58 Å) Ta(2)-Ni(3) bond length. There are a spread of Ta(2)-Ni(1) bond distances ranging from 2.57-2.60 Å. There are four inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one Ta(1), three equivalent Ta(2), one Ni(2), one Ni(4), three equivalent Ni(1), and three equivalent Ni(3) atoms to form distorted NiTa4Ni8 cuboctahedra that share corners with two equivalent Ta(1)Ni12 cuboctahedra, corners with two equivalent Ni(4)Ta4Ni8 cuboctahedra, corners with five equivalent Ni(2)Ta4Ni8 cuboctahedra, corners with six equivalent Ni(1)Ta4Ni8 cuboctahedra, edges with three equivalent Ta(1)Ni12 cuboctahedra, edges with three equivalent Ni(2)Ta4Ni8 cuboctahedra, edges with three equivalent Ni(4)Ta4Ni8 cuboctahedra, edges with four equivalent Ta(2)Ni12 cuboctahedra, edges with four equivalent Ni(1)Ta4Ni8 cuboctahedra, edges with four equivalent Ni(3)Ta4Ni8 cuboctahedra,  a faceface with one Ta(1)Ni12 cuboctahedra,  a faceface with one Ni(4)Ta4Ni8 cuboctahedra, faces with three equivalent Ta(2)Ni12 cuboctahedra, faces with three equivalent Ni(3)Ta4Ni8 cuboctahedra, faces with five equivalent Ni(2)Ta4Ni8 cuboctahedra, and faces with six equivalent Ni(1)Ta4Ni8 cuboctahedra. The Ni(1)-Ni(2) bond length is 2.55 Å. The Ni(1)-Ni(4) bond length is 2.59 Å. There are two shorter (2.53 Å) and one longer (2.55 Å) Ni(1)-Ni(1) bond length. There are a spread of Ni(1)-Ni(3) bond distances ranging from 2.56-2.60 Å. In the second Ni site, Ni(2) is bonded to one Ta(2), three equivalent Ta(1), one Ni(1), one Ni(3), three equivalent Ni(2), and three equivalent Ni(4) atoms to form distorted NiTa4Ni8 cuboctahedra that share corners with two equivalent Ta(2)Ni12 cuboctahedra, corners with two equivalent Ni(3)Ta4Ni8 cuboctahedra, corners with five equivalent Ni(1)Ta4Ni8 cuboctahedra, corners with six equivalent Ni(2)Ta4Ni8 cuboctahedra, edges with three equivalent Ta(2)Ni12 cuboctahedra, edges with three equivalent Ni(1)Ta4Ni8 cuboctahedra, edges with three equivalent Ni(3)Ta4Ni8 cuboctahedra, edges with four equivalent Ta(1)Ni12 cuboctahedra, edges with four equivalent Ni(2)Ta4Ni8 cuboctahedra, edges with four equivalent Ni(4)Ta4Ni8 cuboctahedra,  a faceface with one Ta(2)Ni12 cuboctahedra,  a faceface with one Ni(3)Ta4Ni8 cuboctahedra, faces with three equivalent Ta(1)Ni12 cuboctahedra, faces with three equivalent Ni(4)Ta4Ni8 cuboctahedra, faces with five equivalent Ni(1)Ta4Ni8 cuboctahedra, and faces with six equivalent Ni(2)Ta4Ni8 cuboctahedra. The Ni(2)-Ni(3) bond length is 2.55 Å. There is one shorter (2.51 Å) and two longer (2.57 Å) Ni(2)-Ni(2) bond lengths. There are a spread of Ni(2)-Ni(4) bond distances ranging from 2.52-2.66 Å. In the third Ni site, Ni(3) is bonded to one Ta(1), three equivalent Ta(2), two equivalent Ni(2), and six equivalent Ni(1) atoms to form distorted NiTa4Ni8 cuboctahedra that share  a cornercorner with one Ni(4)Ta4Ni8 cuboctahedra, corners with two equivalent Ni(3)Ta4Ni8 cuboctahedra, corners with four equivalent Ta(1)Ni12 cuboctahedra, corners with four equivalent Ta(2)Ni12 cuboctahedra, corners with four equivalent Ni(2)Ta4Ni8 cuboctahedra, edges with three equivalent Ni(4)Ta4Ni8 cuboctahedra, edges with four equivalent Ni(3)Ta4Ni8 cuboctahedra, edges with six equivalent Ni(2)Ta4Ni8 cuboctahedra, edges with eight equivalent Ni(1)Ta4Ni8 cuboctahedra, faces with two equivalent Ta(1)Ni12 cuboctahedra, faces with two equivalent Ni(2)Ta4Ni8 cuboctahedra, faces with two equivalent Ni(3)Ta4Ni8 cuboctahedra, faces with three equivalent Ni(4)Ta4Ni8 cuboctahedra, faces with four equivalent Ta(2)Ni12 cuboctahedra, and faces with six equivalent Ni(1)Ta4Ni8 cuboctahedra. In the fourth Ni site, Ni(4) is bonded to one Ta(2), three equivalent Ta(1), two equivalent Ni(1), and six equivalent Ni(2) atoms to form distorted NiTa4Ni8 cuboctahedra that share  a cornercorner with one Ni(3)Ta4Ni8 cuboctahedra, corners with two equivalent Ni(4)Ta4Ni8 cuboctahedra, corners with four equivalent Ta(1)Ni12 cuboctahedra, corners with four equivalent Ta(2)Ni12 cuboctahedra, corners with four equivalent Ni(1)Ta4Ni8 cuboctahedra, edges with three equivalent Ni(3)Ta4Ni8 cuboctahedra, edges with four equivalent Ni(4)Ta4Ni8 cuboctahedra, edges with six equivalent Ni(1)Ta4Ni8 cuboctahedra, edges with eight equivalent Ni(2)Ta4Ni8 cuboctahedra, faces with two equivalent Ta(2)Ni12 cuboctahedra, faces with two equivalent Ni(1)Ta4Ni8 cuboctahedra, faces with two equivalent Ni(4)Ta4Ni8 cuboctahedra, faces with three equivalent Ni(3)Ta4Ni8 cuboctahedra, faces with four equivalent Ta(1)Ni12 cuboctahedra, and faces with six equivalent Ni(2)Ta4Ni8 cuboctahedra.