Ni15Al4Sb is Uranium Silicide-derived structured and crystallizes in the tetragonal P4/mmm space group. There are seven inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to eight Ni(4,4) and four equivalent Sb(1) atoms to form NiNi8Sb4 cuboctahedra that share corners with four equivalent Ni(1)Ni8Sb4 cuboctahedra; corners with eight equivalent Ni(2)Al4Ni8 cuboctahedra; edges with eight equivalent Al(1)Ni12 cuboctahedra; edges with sixteen Ni(4,4)Al2Ni8Sb2 cuboctahedra; faces with two equivalent Ni(2)Al4Ni8 cuboctahedra; faces with four equivalent Ni(1)Ni8Sb4 cuboctahedra; faces with four equivalent Sb(1)Ni12 cuboctahedra; and faces with eight Ni(4,4)Al2Ni8Sb2 cuboctahedra. In the second Ni site, Ni(2) is bonded to four equivalent Ni(4), four equivalent Ni(5), and four equivalent Al(1) atoms to form NiAl4Ni8 cuboctahedra that share corners with four equivalent Ni(2)Al4Ni8 cuboctahedra, corners with four equivalent Ni(3)Al4Ni8 cuboctahedra, corners with four equivalent Ni(1)Ni8Sb4 cuboctahedra, edges with four equivalent Al(2)Ni12 cuboctahedra, edges with four equivalent Sb(1)Ni12 cuboctahedra, edges with eight equivalent Ni(4)Al2Ni8Sb2 cuboctahedra, edges with eight equivalent Ni(5)Al4Ni8 cuboctahedra,  a faceface with one Ni(3)Al4Ni8 cuboctahedra,  a faceface with one Ni(1)Ni8Sb4 cuboctahedra, faces with four equivalent Ni(4)Al2Ni8Sb2 cuboctahedra, faces with four equivalent Ni(2)Al4Ni8 cuboctahedra, faces with four equivalent Ni(5)Al4Ni8 cuboctahedra, and faces with four equivalent Al(1)Ni12 cuboctahedra. In the third Ni site, Ni(3) is bonded to four equivalent Ni(5), four equivalent Ni(6), and four equivalent Al(2) atoms to form NiAl4Ni8 cuboctahedra that share corners with four equivalent Ni(2)Al4Ni8 cuboctahedra, corners with eight equivalent Ni(3)Al4Ni8 cuboctahedra, edges with four equivalent Al(1)Ni12 cuboctahedra, edges with four equivalent Al(2)Ni12 cuboctahedra, edges with eight equivalent Ni(5)Al4Ni8 cuboctahedra, edges with eight equivalent Ni(6)Al4Ni8 cuboctahedra,  a faceface with one Ni(2)Al4Ni8 cuboctahedra, faces with four equivalent Ni(5)Al4Ni8 cuboctahedra, faces with four equivalent Ni(6)Al4Ni8 cuboctahedra, faces with four equivalent Al(2)Ni12 cuboctahedra, and faces with five equivalent Ni(3)Al4Ni8 cuboctahedra. In the fourth Ni site, Ni(4) is bonded to two equivalent Ni(1), two equivalent Ni(2), four equivalent Ni(4), two equivalent Al(1), and two equivalent Sb(1) atoms to form distorted NiAl2Ni8Sb2 cuboctahedra that share corners with four equivalent Ni(5)Al4Ni8 cuboctahedra; corners with eight Ni(4,4)Al2Ni8Sb2 cuboctahedra; edges with four equivalent Ni(4)Al2Ni8Sb2 cuboctahedra; edges with four equivalent Ni(2)Al4Ni8 cuboctahedra; edges with four equivalent Ni(5)Al4Ni8 cuboctahedra; edges with four equivalent Ni(1)Ni8Sb4 cuboctahedra; edges with four equivalent Al(1)Ni12 cuboctahedra; edges with four equivalent Sb(1)Ni12 cuboctahedra;  a faceface with one Ni(5)Al4Ni8 cuboctahedra; faces with two equivalent Ni(2)Al4Ni8 cuboctahedra; faces with two equivalent Ni(1)Ni8Sb4 cuboctahedra; faces with two equivalent Al(1)Ni12 cuboctahedra; faces with two equivalent Sb(1)Ni12 cuboctahedra; and faces with nine Ni(4,4)Al2Ni8Sb2 cuboctahedra. In the fifth Ni site, Ni(5) is bonded to two equivalent Ni(2), two equivalent Ni(3), four equivalent Ni(5), two equivalent Al(1), and two equivalent Al(2) atoms to form distorted NiAl4Ni8 cuboctahedra that share corners with four equivalent Ni(4)Al2Ni8Sb2 cuboctahedra, corners with four equivalent Ni(5)Al4Ni8 cuboctahedra, corners with four equivalent Ni(6)Al4Ni8 cuboctahedra, edges with four equivalent Ni(4)Al2Ni8Sb2 cuboctahedra, edges with four equivalent Ni(2)Al4Ni8 cuboctahedra, edges with four equivalent Ni(3)Al4Ni8 cuboctahedra, edges with four equivalent Ni(6)Al4Ni8 cuboctahedra, edges with four equivalent Al(1)Ni12 cuboctahedra, edges with four equivalent Al(2)Ni12 cuboctahedra,  a faceface with one Ni(4)Al2Ni8Sb2 cuboctahedra,  a faceface with one Ni(6)Al4Ni8 cuboctahedra, faces with two equivalent Ni(2)Al4Ni8 cuboctahedra, faces with two equivalent Ni(3)Al4Ni8 cuboctahedra, faces with two equivalent Al(1)Ni12 cuboctahedra, faces with two equivalent Al(2)Ni12 cuboctahedra, and faces with eight equivalent Ni(5)Al4Ni8 cuboctahedra. In the sixth Ni site, Ni(6) is bonded to four equivalent Ni(3), four equivalent Ni(6), and four equivalent Al(2) atoms to form NiAl4Ni8 cuboctahedra that share corners with four equivalent Ni(6)Al4Ni8 cuboctahedra, corners with eight equivalent Ni(5)Al4Ni8 cuboctahedra, edges with eight equivalent Ni(3)Al4Ni8 cuboctahedra, edges with eight equivalent Ni(5)Al4Ni8 cuboctahedra, edges with eight equivalent Al(2)Ni12 cuboctahedra, faces with two equivalent Ni(5)Al4Ni8 cuboctahedra, faces with four equivalent Ni(3)Al4Ni8 cuboctahedra, faces with four equivalent Al(2)Ni12 cuboctahedra, and faces with eight equivalent Ni(6)Al4Ni8 cuboctahedra. In the seventh Ni site, Ni(4) is bonded to two equivalent Ni(1), two equivalent Ni(2), four equivalent Ni(4), two equivalent Al(1), and two equivalent Sb(1) atoms to form distorted NiAl2Ni8Sb2 cuboctahedra that share corners with four equivalent Ni(5)Al4Ni8 cuboctahedra; corners with eight Ni(4,4)Al2Ni8Sb2 cuboctahedra; edges with four equivalent Ni(4)Al2Ni8Sb2 cuboctahedra; edges with four equivalent Ni(2)Al4Ni8 cuboctahedra; edges with four equivalent Ni(5)Al4Ni8 cuboctahedra; edges with four equivalent Ni(1)Ni8Sb4 cuboctahedra; edges with four equivalent Al(1)Ni12 cuboctahedra; edges with four equivalent Sb(1)Ni12 cuboctahedra;  a faceface with one Ni(5)Al4Ni8 cuboctahedra; faces with two equivalent Ni(2)Al4Ni8 cuboctahedra; faces with two equivalent Ni(1)Ni8Sb4 cuboctahedra; faces with two equivalent Al(1)Ni12 cuboctahedra; faces with two equivalent Sb(1)Ni12 cuboctahedra; and faces with nine Ni(4,4)Al2Ni8Sb2 cuboctahedra. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to four equivalent Ni(2), four equivalent Ni(4), and four equivalent Ni(5) atoms to form AlNi12 cuboctahedra that share corners with four equivalent Al(1)Ni12 cuboctahedra, corners with four equivalent Al(2)Ni12 cuboctahedra, corners with four equivalent Sb(1)Ni12 cuboctahedra, edges with four equivalent Ni(3)Al4Ni8 cuboctahedra, edges with four equivalent Ni(1)Ni8Sb4 cuboctahedra, edges with eight equivalent Ni(4)Al2Ni8Sb2 cuboctahedra, edges with eight equivalent Ni(5)Al4Ni8 cuboctahedra,  a faceface with one Al(2)Ni12 cuboctahedra,  a faceface with one Sb(1)Ni12 cuboctahedra, faces with four equivalent Ni(4)Al2Ni8Sb2 cuboctahedra, faces with four equivalent Ni(2)Al4Ni8 cuboctahedra, faces with four equivalent Ni(5)Al4Ni8 cuboctahedra, and faces with four equivalent Al(1)Ni12 cuboctahedra. In the second Al site, Al(2) is bonded to four equivalent Ni(3), four equivalent Ni(5), and four equivalent Ni(6) atoms to form AlNi12 cuboctahedra that share corners with four equivalent Al(1)Ni12 cuboctahedra, corners with eight equivalent Al(2)Ni12 cuboctahedra, edges with four equivalent Ni(2)Al4Ni8 cuboctahedra, edges with four equivalent Ni(3)Al4Ni8 cuboctahedra, edges with eight equivalent Ni(5)Al4Ni8 cuboctahedra, edges with eight equivalent Ni(6)Al4Ni8 cuboctahedra,  a faceface with one Al(1)Ni12 cuboctahedra, faces with four equivalent Ni(3)Al4Ni8 cuboctahedra, faces with four equivalent Ni(5)Al4Ni8 cuboctahedra, faces with four equivalent Ni(6)Al4Ni8 cuboctahedra, and faces with five equivalent Al(2)Ni12 cuboctahedra. Sb(1) is bonded to four equivalent Ni(1) and eight Ni(4,4) atoms to form SbNi12 cuboctahedra that share corners with four equivalent Sb(1)Ni12 cuboctahedra; corners with eight equivalent Al(1)Ni12 cuboctahedra; edges with eight equivalent Ni(2)Al4Ni8 cuboctahedra; edges with sixteen Ni(4,4)Al2Ni8Sb2 cuboctahedra; faces with two equivalent Al(1)Ni12 cuboctahedra; faces with four equivalent Ni(1)Ni8Sb4 cuboctahedra; faces with four equivalent Sb(1)Ni12 cuboctahedra; and faces with eight Ni(4,4)Al2Ni8Sb2 cuboctahedra.
Ni15Al4Sb is Uranium Silicide-derived structured and crystallizes in the tetragonal P4/mmm space group. There are seven inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to eight Ni(4,4) and four equivalent Sb(1) atoms to form NiNi8Sb4 cuboctahedra that share corners with four equivalent Ni(1)Ni8Sb4 cuboctahedra; corners with eight equivalent Ni(2)Al4Ni8 cuboctahedra; edges with eight equivalent Al(1)Ni12 cuboctahedra; edges with sixteen Ni(4,4)Al2Ni8Sb2 cuboctahedra; faces with two equivalent Ni(2)Al4Ni8 cuboctahedra; faces with four equivalent Ni(1)Ni8Sb4 cuboctahedra; faces with four equivalent Sb(1)Ni12 cuboctahedra; and faces with eight Ni(4,4)Al2Ni8Sb2 cuboctahedra. All Ni(1)-Ni(4,4) bond lengths are 2.62 Å. All Ni(1)-Sb(1) bond lengths are 2.55 Å. In the second Ni site, Ni(2) is bonded to four equivalent Ni(4), four equivalent Ni(5), and four equivalent Al(1) atoms to form NiAl4Ni8 cuboctahedra that share corners with four equivalent Ni(2)Al4Ni8 cuboctahedra, corners with four equivalent Ni(3)Al4Ni8 cuboctahedra, corners with four equivalent Ni(1)Ni8Sb4 cuboctahedra, edges with four equivalent Al(2)Ni12 cuboctahedra, edges with four equivalent Sb(1)Ni12 cuboctahedra, edges with eight equivalent Ni(4)Al2Ni8Sb2 cuboctahedra, edges with eight equivalent Ni(5)Al4Ni8 cuboctahedra,  a faceface with one Ni(3)Al4Ni8 cuboctahedra,  a faceface with one Ni(1)Ni8Sb4 cuboctahedra, faces with four equivalent Ni(4)Al2Ni8Sb2 cuboctahedra, faces with four equivalent Ni(2)Al4Ni8 cuboctahedra, faces with four equivalent Ni(5)Al4Ni8 cuboctahedra, and faces with four equivalent Al(1)Ni12 cuboctahedra. All Ni(2)-Ni(4) bond lengths are 2.51 Å. All Ni(2)-Ni(5) bond lengths are 2.52 Å. All Ni(2)-Al(1) bond lengths are 2.55 Å. In the third Ni site, Ni(3) is bonded to four equivalent Ni(5), four equivalent Ni(6), and four equivalent Al(2) atoms to form NiAl4Ni8 cuboctahedra that share corners with four equivalent Ni(2)Al4Ni8 cuboctahedra, corners with eight equivalent Ni(3)Al4Ni8 cuboctahedra, edges with four equivalent Al(1)Ni12 cuboctahedra, edges with four equivalent Al(2)Ni12 cuboctahedra, edges with eight equivalent Ni(5)Al4Ni8 cuboctahedra, edges with eight equivalent Ni(6)Al4Ni8 cuboctahedra,  a faceface with one Ni(2)Al4Ni8 cuboctahedra, faces with four equivalent Ni(5)Al4Ni8 cuboctahedra, faces with four equivalent Ni(6)Al4Ni8 cuboctahedra, faces with four equivalent Al(2)Ni12 cuboctahedra, and faces with five equivalent Ni(3)Al4Ni8 cuboctahedra. All Ni(3)-Ni(5) bond lengths are 2.51 Å. All Ni(3)-Ni(6) bond lengths are 2.53 Å. All Ni(3)-Al(2) bond lengths are 2.55 Å. In the fourth Ni site, Ni(4) is bonded to two equivalent Ni(1), two equivalent Ni(2), four equivalent Ni(4), two equivalent Al(1), and two equivalent Sb(1) atoms to form distorted NiAl2Ni8Sb2 cuboctahedra that share corners with four equivalent Ni(5)Al4Ni8 cuboctahedra; corners with eight Ni(4,4)Al2Ni8Sb2 cuboctahedra; edges with four equivalent Ni(4)Al2Ni8Sb2 cuboctahedra; edges with four equivalent Ni(2)Al4Ni8 cuboctahedra; edges with four equivalent Ni(5)Al4Ni8 cuboctahedra; edges with four equivalent Ni(1)Ni8Sb4 cuboctahedra; edges with four equivalent Al(1)Ni12 cuboctahedra; edges with four equivalent Sb(1)Ni12 cuboctahedra;  a faceface with one Ni(5)Al4Ni8 cuboctahedra; faces with two equivalent Ni(2)Al4Ni8 cuboctahedra; faces with two equivalent Ni(1)Ni8Sb4 cuboctahedra; faces with two equivalent Al(1)Ni12 cuboctahedra; faces with two equivalent Sb(1)Ni12 cuboctahedra; and faces with nine Ni(4,4)Al2Ni8Sb2 cuboctahedra. All Ni(4)-Ni(4) bond lengths are 2.55 Å. Both Ni(4)-Al(1) bond lengths are 2.53 Å. Both Ni(4)-Sb(1) bond lengths are 2.62 Å. In the fifth Ni site, Ni(5) is bonded to two equivalent Ni(2), two equivalent Ni(3), four equivalent Ni(5), two equivalent Al(1), and two equivalent Al(2) atoms to form distorted NiAl4Ni8 cuboctahedra that share corners with four equivalent Ni(4)Al2Ni8Sb2 cuboctahedra, corners with four equivalent Ni(5)Al4Ni8 cuboctahedra, corners with four equivalent Ni(6)Al4Ni8 cuboctahedra, edges with four equivalent Ni(4)Al2Ni8Sb2 cuboctahedra, edges with four equivalent Ni(2)Al4Ni8 cuboctahedra, edges with four equivalent Ni(3)Al4Ni8 cuboctahedra, edges with four equivalent Ni(6)Al4Ni8 cuboctahedra, edges with four equivalent Al(1)Ni12 cuboctahedra, edges with four equivalent Al(2)Ni12 cuboctahedra,  a faceface with one Ni(4)Al2Ni8Sb2 cuboctahedra,  a faceface with one Ni(6)Al4Ni8 cuboctahedra, faces with two equivalent Ni(2)Al4Ni8 cuboctahedra, faces with two equivalent Ni(3)Al4Ni8 cuboctahedra, faces with two equivalent Al(1)Ni12 cuboctahedra, faces with two equivalent Al(2)Ni12 cuboctahedra, and faces with eight equivalent Ni(5)Al4Ni8 cuboctahedra. All Ni(5)-Ni(5) bond lengths are 2.55 Å. Both Ni(5)-Al(1) bond lengths are 2.50 Å. Both Ni(5)-Al(2) bond lengths are 2.51 Å. In the sixth Ni site, Ni(6) is bonded to four equivalent Ni(3), four equivalent Ni(6), and four equivalent Al(2) atoms to form NiAl4Ni8 cuboctahedra that share corners with four equivalent Ni(6)Al4Ni8 cuboctahedra, corners with eight equivalent Ni(5)Al4Ni8 cuboctahedra, edges with eight equivalent Ni(3)Al4Ni8 cuboctahedra, edges with eight equivalent Ni(5)Al4Ni8 cuboctahedra, edges with eight equivalent Al(2)Ni12 cuboctahedra, faces with two equivalent Ni(5)Al4Ni8 cuboctahedra, faces with four equivalent Ni(3)Al4Ni8 cuboctahedra, faces with four equivalent Al(2)Ni12 cuboctahedra, and faces with eight equivalent Ni(6)Al4Ni8 cuboctahedra. All Ni(6)-Ni(6) bond lengths are 2.55 Å. All Ni(6)-Al(2) bond lengths are 2.53 Å. In the seventh Ni site, Ni(4) is bonded to two equivalent Ni(1), two equivalent Ni(2), four equivalent Ni(4), two equivalent Al(1), and two equivalent Sb(1) atoms to form distorted NiAl2Ni8Sb2 cuboctahedra that share corners with four equivalent Ni(5)Al4Ni8 cuboctahedra; corners with eight Ni(4,4)Al2Ni8Sb2 cuboctahedra; edges with four equivalent Ni(4)Al2Ni8Sb2 cuboctahedra; edges with four equivalent Ni(2)Al4Ni8 cuboctahedra; edges with four equivalent Ni(5)Al4Ni8 cuboctahedra; edges with four equivalent Ni(1)Ni8Sb4 cuboctahedra; edges with four equivalent Al(1)Ni12 cuboctahedra; edges with four equivalent Sb(1)Ni12 cuboctahedra;  a faceface with one Ni(5)Al4Ni8 cuboctahedra; faces with two equivalent Ni(2)Al4Ni8 cuboctahedra; faces with two equivalent Ni(1)Ni8Sb4 cuboctahedra; faces with two equivalent Al(1)Ni12 cuboctahedra; faces with two equivalent Sb(1)Ni12 cuboctahedra; and faces with nine Ni(4,4)Al2Ni8Sb2 cuboctahedra. Both Ni(4)-Ni(2) bond lengths are 2.51 Å. All Ni(4)-Ni(4) bond lengths are 2.55 Å. Both Ni(4)-Al(1) bond lengths are 2.53 Å. Both Ni(4)-Sb(1) bond lengths are 2.62 Å. There are two inequivalent Al sites. In the first Al site, Al(1) is bonded to four equivalent Ni(2), four equivalent Ni(4), and four equivalent Ni(5) atoms to form AlNi12 cuboctahedra that share corners with four equivalent Al(1)Ni12 cuboctahedra, corners with four equivalent Al(2)Ni12 cuboctahedra, corners with four equivalent Sb(1)Ni12 cuboctahedra, edges with four equivalent Ni(3)Al4Ni8 cuboctahedra, edges with four equivalent Ni(1)Ni8Sb4 cuboctahedra, edges with eight equivalent Ni(4)Al2Ni8Sb2 cuboctahedra, edges with eight equivalent Ni(5)Al4Ni8 cuboctahedra,  a faceface with one Al(2)Ni12 cuboctahedra,  a faceface with one Sb(1)Ni12 cuboctahedra, faces with four equivalent Ni(4)Al2Ni8Sb2 cuboctahedra, faces with four equivalent Ni(2)Al4Ni8 cuboctahedra, faces with four equivalent Ni(5)Al4Ni8 cuboctahedra, and faces with four equivalent Al(1)Ni12 cuboctahedra. In the second Al site, Al(2) is bonded to four equivalent Ni(3), four equivalent Ni(5), and four equivalent Ni(6) atoms to form AlNi12 cuboctahedra that share corners with four equivalent Al(1)Ni12 cuboctahedra, corners with eight equivalent Al(2)Ni12 cuboctahedra, edges with four equivalent Ni(2)Al4Ni8 cuboctahedra, edges with four equivalent Ni(3)Al4Ni8 cuboctahedra, edges with eight equivalent Ni(5)Al4Ni8 cuboctahedra, edges with eight equivalent Ni(6)Al4Ni8 cuboctahedra,  a faceface with one Al(1)Ni12 cuboctahedra, faces with four equivalent Ni(3)Al4Ni8 cuboctahedra, faces with four equivalent Ni(5)Al4Ni8 cuboctahedra, faces with four equivalent Ni(6)Al4Ni8 cuboctahedra, and faces with five equivalent Al(2)Ni12 cuboctahedra. Sb(1) is bonded to four equivalent Ni(1) and eight Ni(4,4) atoms to form SbNi12 cuboctahedra that share corners with four equivalent Sb(1)Ni12 cuboctahedra; corners with eight equivalent Al(1)Ni12 cuboctahedra; edges with eight equivalent Ni(2)Al4Ni8 cuboctahedra; edges with sixteen Ni(4,4)Al2Ni8Sb2 cuboctahedra; faces with two equivalent Al(1)Ni12 cuboctahedra; faces with four equivalent Ni(1)Ni8Sb4 cuboctahedra; faces with four equivalent Sb(1)Ni12 cuboctahedra; and faces with eight Ni(4,4)Al2Ni8Sb2 cuboctahedra.