Co3Ta is beta Cu3Ti-like structured and crystallizes in the trigonal R-3m space group. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to six Co(1,1,1) and six Co(2,2,2,2) atoms to form TaCo12 cuboctahedra that share corners with six equivalent Ta(1)Co12 cuboctahedra; corners with twelve Co(2,2,2)Ta4Co8 cuboctahedra; edges with six Co(1,1,1)Ta4Co8 cuboctahedra; edges with twelve Co(2,2,2,2)Ta4Co8 cuboctahedra; faces with six Co(1,1,1)Ta4Co8 cuboctahedra; faces with six Co(2,2,2,2)Ta4Co8 cuboctahedra; and faces with eight equivalent Ta(2)Co12 cuboctahedra. In the second Ta site, Ta(2) is bonded to three Co(1,1) and nine Co(2,2,2) atoms to form TaCo12 cuboctahedra that share corners with six Co(1,1,1)Ta4Co8 cuboctahedra; corners with nine equivalent Ta(2)Co12 cuboctahedra; edges with six Co(1,1)Ta4Co8 cuboctahedra; edges with fifteen Co(2,2,2,2)Ta4Co8 cuboctahedra; faces with three equivalent Ta(2)Co12 cuboctahedra; faces with three Co(1,1)Ta4Co8 cuboctahedra; faces with four equivalent Ta(1)Co12 cuboctahedra; and faces with nine Co(2,2,2)Ta4Co8 cuboctahedra. There are twelve inequivalent Co sites. In the first Co site, Co(2) is bonded to one Ta(1); three equivalent Ta(2); two Co(1,1); and six Co(2,2) atoms to form distorted CoTa4Co8 cuboctahedra that share corners with two equivalent Ta(1)Co12 cuboctahedra; corners with four Co(1,1)Ta4Co8 cuboctahedra; corners with nine Co(2,2)Ta4Co8 cuboctahedra; edges with two equivalent Ta(1)Co12 cuboctahedra; edges with four Co(1,1)Ta4Co8 cuboctahedra; edges with five equivalent Ta(2)Co12 cuboctahedra; edges with ten Co(2,2,2)Ta4Co8 cuboctahedra;  a faceface with one Ta(1)Co12 cuboctahedra; faces with three equivalent Ta(2)Co12 cuboctahedra; faces with six Co(1,1,1,1)Ta4Co8 cuboctahedra; and faces with nine Co(2,2,2)Ta4Co8 cuboctahedra. In the second Co site, Co(1) is bonded to two equivalent Ta(1); two equivalent Ta(2); four Co(1,1); and four Co(2,2,2,2) atoms to form CoTa4Co8 cuboctahedra that share corners with four equivalent Ta(2)Co12 cuboctahedra; corners with six equivalent Co(1)Ta4Co8 cuboctahedra; corners with eight Co(2,2,2)Ta4Co8 cuboctahedra; edges with two equivalent Ta(1)Co12 cuboctahedra; edges with four equivalent Ta(2)Co12 cuboctahedra; edges with four Co(1,1)Ta4Co8 cuboctahedra; edges with eight Co(2,2,2,2)Ta4Co8 cuboctahedra; faces with two equivalent Ta(1)Co12 cuboctahedra; faces with two equivalent Ta(2)Co12 cuboctahedra; faces with four Co(1,1)Ta4Co8 cuboctahedra; and faces with twelve Co(2,2,2,2)Ta4Co8 cuboctahedra. In the third Co site, Co(1) is bonded to two equivalent Ta(1); two equivalent Ta(2); four Co(1,1); and four Co(2,2) atoms to form CoTa4Co8 cuboctahedra that share corners with four equivalent Ta(2)Co12 cuboctahedra; corners with six equivalent Co(1)Ta4Co8 cuboctahedra; corners with eight Co(2,2,2)Ta4Co8 cuboctahedra; edges with two equivalent Ta(1)Co12 cuboctahedra; edges with four equivalent Ta(2)Co12 cuboctahedra; edges with four Co(1,1)Ta4Co8 cuboctahedra; edges with eight Co(2,2)Ta4Co8 cuboctahedra; faces with two equivalent Ta(1)Co12 cuboctahedra; faces with two equivalent Ta(2)Co12 cuboctahedra; faces with four Co(1,1)Ta4Co8 cuboctahedra; and faces with twelve Co(2,2,2,2)Ta4Co8 cuboctahedra. In the fourth Co site, Co(1) is bonded to two equivalent Ta(1); two equivalent Ta(2); four Co(1,1); and four Co(2,2,2) atoms to form CoTa4Co8 cuboctahedra that share corners with four equivalent Ta(2)Co12 cuboctahedra; corners with six equivalent Co(1)Ta4Co8 cuboctahedra; corners with eight equivalent Co(2)Ta4Co8 cuboctahedra; edges with two equivalent Ta(1)Co12 cuboctahedra; edges with four equivalent Ta(2)Co12 cuboctahedra; edges with four Co(1,1)Ta4Co8 cuboctahedra; edges with eight Co(2,2,2)Ta4Co8 cuboctahedra; faces with two equivalent Ta(1)Co12 cuboctahedra; faces with two equivalent Ta(2)Co12 cuboctahedra; faces with four Co(1,1)Ta4Co8 cuboctahedra; and faces with twelve Co(2,2,2,2,2,2)Ta4Co8 cuboctahedra. In the fifth Co site, Co(2) is bonded to one Ta(1); three equivalent Ta(2); two Co(1,1); and six Co(2,2) atoms to form distorted CoTa4Co8 cuboctahedra that share corners with two equivalent Ta(1)Co12 cuboctahedra; corners with four Co(1,1)Ta4Co8 cuboctahedra; corners with nine Co(2,2)Ta4Co8 cuboctahedra; edges with two equivalent Ta(1)Co12 cuboctahedra; edges with four Co(1,1)Ta4Co8 cuboctahedra; edges with five equivalent Ta(2)Co12 cuboctahedra; edges with ten Co(2,2,2)Ta4Co8 cuboctahedra;  a faceface with one Ta(1)Co12 cuboctahedra; faces with three equivalent Ta(2)Co12 cuboctahedra; faces with six Co(1,1,1)Ta4Co8 cuboctahedra; and faces with nine Co(2,2)Ta4Co8 cuboctahedra. In the sixth Co site, Co(2) is bonded to one Ta(1); three equivalent Ta(2); two Co(1,1); and six Co(2,2,2) atoms to form distorted CoTa4Co8 cuboctahedra that share corners with two equivalent Ta(1)Co12 cuboctahedra; corners with four Co(1,1)Ta4Co8 cuboctahedra; corners with nine Co(2,2)Ta4Co8 cuboctahedra; edges with two equivalent Ta(1)Co12 cuboctahedra; edges with four Co(1,1)Ta4Co8 cuboctahedra; edges with five equivalent Ta(2)Co12 cuboctahedra; edges with ten Co(2,2,2)Ta4Co8 cuboctahedra;  a faceface with one Ta(1)Co12 cuboctahedra; faces with three equivalent Ta(2)Co12 cuboctahedra; faces with six Co(1,1,1)Ta4Co8 cuboctahedra; and faces with nine Co(2,2,2)Ta4Co8 cuboctahedra. In the seventh Co site, Co(2) is bonded to one Ta(1); three equivalent Ta(2); two Co(1,1); and six Co(2,2) atoms to form distorted CoTa4Co8 cuboctahedra that share corners with two equivalent Ta(1)Co12 cuboctahedra; corners with four equivalent Co(1)Ta4Co8 cuboctahedra; corners with nine Co(2,2)Ta4Co8 cuboctahedra; edges with two equivalent Ta(1)Co12 cuboctahedra; edges with four Co(1,1)Ta4Co8 cuboctahedra; edges with five equivalent Ta(2)Co12 cuboctahedra; edges with ten Co(2,2,2)Ta4Co8 cuboctahedra;  a faceface with one Ta(1)Co12 cuboctahedra; faces with three equivalent Ta(2)Co12 cuboctahedra; faces with six Co(1,1,1,1)Ta4Co8 cuboctahedra; and faces with nine Co(2,2)Ta4Co8 cuboctahedra. In the eighth Co site, Co(1) is bonded to two equivalent Ta(1); two equivalent Ta(2); four Co(1,1); and four Co(2,2,2) atoms to form CoTa4Co8 cuboctahedra that share corners with four equivalent Ta(2)Co12 cuboctahedra; corners with six equivalent Co(1)Ta4Co8 cuboctahedra; corners with eight Co(2,2,2)Ta4Co8 cuboctahedra; edges with two equivalent Ta(1)Co12 cuboctahedra; edges with four equivalent Ta(2)Co12 cuboctahedra; edges with four Co(1,1)Ta4Co8 cuboctahedra; edges with eight Co(2,2,2)Ta4Co8 cuboctahedra; faces with two equivalent Ta(1)Co12 cuboctahedra; faces with two equivalent Ta(2)Co12 cuboctahedra; faces with four Co(1,1)Ta4Co8 cuboctahedra; and faces with twelve Co(2,2,2,2)Ta4Co8 cuboctahedra. In the ninth Co site, Co(1) is bonded to two equivalent Ta(1); two equivalent Ta(2); four equivalent Co(1); and four Co(2,2,2,2) atoms to form CoTa4Co8 cuboctahedra that share corners with four equivalent Ta(2)Co12 cuboctahedra; corners with six equivalent Co(1)Ta4Co8 cuboctahedra; corners with eight Co(2,2)Ta4Co8 cuboctahedra; edges with two equivalent Ta(1)Co12 cuboctahedra; edges with four equivalent Ta(2)Co12 cuboctahedra; edges with four equivalent Co(1)Ta4Co8 cuboctahedra; edges with eight Co(2,2,2,2)Ta4Co8 cuboctahedra; faces with two equivalent Ta(1)Co12 cuboctahedra; faces with two equivalent Ta(2)Co12 cuboctahedra; faces with four equivalent Co(1)Ta4Co8 cuboctahedra; and faces with twelve Co(2,2,2,2,2)Ta4Co8 cuboctahedra. In the tenth Co site, Co(2) is bonded to one Ta(1); three equivalent Ta(2); two Co(1,1); and six Co(2,2,2) atoms to form distorted CoTa4Co8 cuboctahedra that share corners with two equivalent Ta(1)Co12 cuboctahedra; corners with four equivalent Co(1)Ta4Co8 cuboctahedra; corners with nine Co(2,2)Ta4Co8 cuboctahedra; edges with two equivalent Ta(1)Co12 cuboctahedra; edges with four Co(1,1)Ta4Co8 cuboctahedra; edges with five equivalent Ta(2)Co12 cuboctahedra; edges with ten Co(2,2,2,2)Ta4Co8 cuboctahedra;  a faceface with one Ta(1)Co12 cuboctahedra; faces with three equivalent Ta(2)Co12 cuboctahedra; faces with six Co(1,1,1)Ta4Co8 cuboctahedra; and faces with nine Co(2,2,2)Ta4Co8 cuboctahedra. In the eleventh Co site, Co(2) is bonded to one Ta(1); three equivalent Ta(2); two Co(1,1); and six Co(2,2,2) atoms to form distorted CoTa4Co8 cuboctahedra that share corners with two equivalent Ta(1)Co12 cuboctahedra; corners with four Co(1,1)Ta4Co8 cuboctahedra; corners with nine Co(2,2)Ta4Co8 cuboctahedra; edges with two equivalent Ta(1)Co12 cuboctahedra; edges with four Co(1,1)Ta4Co8 cuboctahedra; edges with five equivalent Ta(2)Co12 cuboctahedra; edges with ten Co(2,2,2,2)Ta4Co8 cuboctahedra;  a faceface with one Ta(1)Co12 cuboctahedra; faces with three equivalent Ta(2)Co12 cuboctahedra; faces with six Co(1,1)Ta4Co8 cuboctahedra; and faces with nine Co(2,2,2)Ta4Co8 cuboctahedra. In the twelfth Co site, Co(2) is bonded to one Ta(1); three equivalent Ta(2); two Co(1,1); and six Co(2,2) atoms to form distorted CoTa4Co8 cuboctahedra that share corners with two equivalent Ta(1)Co12 cuboctahedra; corners with four Co(1,1)Ta4Co8 cuboctahedra; corners with nine Co(2,2)Ta4Co8 cuboctahedra; edges with two equivalent Ta(1)Co12 cuboctahedra; edges with four Co(1,1)Ta4Co8 cuboctahedra; edges with five equivalent Ta(2)Co12 cuboctahedra; edges with ten Co(2,2,2)Ta4Co8 cuboctahedra;  a faceface with one Ta(1)Co12 cuboctahedra; faces with three equivalent Ta(2)Co12 cuboctahedra; faces with six Co(1,1,1,1)Ta4Co8 cuboctahedra; and faces with nine Co(2,2,2)Ta4Co8 cuboctahedra.
Co3Ta is beta Cu3Ti-like structured and crystallizes in the trigonal R-3m space group. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to six Co(1,1,1) and six Co(2,2,2,2) atoms to form TaCo12 cuboctahedra that share corners with six equivalent Ta(1)Co12 cuboctahedra; corners with twelve Co(2,2,2)Ta4Co8 cuboctahedra; edges with six Co(1,1,1)Ta4Co8 cuboctahedra; edges with twelve Co(2,2,2,2)Ta4Co8 cuboctahedra; faces with six Co(1,1,1)Ta4Co8 cuboctahedra; faces with six Co(2,2,2,2)Ta4Co8 cuboctahedra; and faces with eight equivalent Ta(2)Co12 cuboctahedra. All Ta(1)-Co(1,1,1) bond lengths are 2.55 Å. All Ta(1)-Co(2,2,2,2) bond lengths are 2.57 Å. In the second Ta site, Ta(2) is bonded to three Co(1,1) and nine Co(2,2,2) atoms to form TaCo12 cuboctahedra that share corners with six Co(1,1,1)Ta4Co8 cuboctahedra; corners with nine equivalent Ta(2)Co12 cuboctahedra; edges with six Co(1,1)Ta4Co8 cuboctahedra; edges with fifteen Co(2,2,2,2)Ta4Co8 cuboctahedra; faces with three equivalent Ta(2)Co12 cuboctahedra; faces with three Co(1,1)Ta4Co8 cuboctahedra; faces with four equivalent Ta(1)Co12 cuboctahedra; and faces with nine Co(2,2,2)Ta4Co8 cuboctahedra. All Ta(2)-Co(1,1) bond lengths are 2.59 Å. There are three shorter (2.55 Å) and six longer (2.56 Å) Ta(2)-Co(2,2,2) bond lengths. There are twelve inequivalent Co sites. In the first Co site, Co(2) is bonded to one Ta(1); three equivalent Ta(2); two Co(1,1); and six Co(2,2) atoms to form distorted CoTa4Co8 cuboctahedra that share corners with two equivalent Ta(1)Co12 cuboctahedra; corners with four Co(1,1)Ta4Co8 cuboctahedra; corners with nine Co(2,2)Ta4Co8 cuboctahedra; edges with two equivalent Ta(1)Co12 cuboctahedra; edges with four Co(1,1)Ta4Co8 cuboctahedra; edges with five equivalent Ta(2)Co12 cuboctahedra; edges with ten Co(2,2,2)Ta4Co8 cuboctahedra;  a faceface with one Ta(1)Co12 cuboctahedra; faces with three equivalent Ta(2)Co12 cuboctahedra; faces with six Co(1,1,1,1)Ta4Co8 cuboctahedra; and faces with nine Co(2,2,2)Ta4Co8 cuboctahedra. The Co(2)-Ta(1) bond length is 2.57 Å. There is one shorter (2.55 Å) and two longer (2.56 Å) Co(2)-Ta(2) bond lengths. Both Co(2)-Co(1,1) bond lengths are 2.50 Å. There are a spread of Co(2)-Co(2,2) bond distances ranging from 2.41-2.70 Å. In the second Co site, Co(1) is bonded to two equivalent Ta(1); two equivalent Ta(2); four Co(1,1); and four Co(2,2,2,2) atoms to form CoTa4Co8 cuboctahedra that share corners with four equivalent Ta(2)Co12 cuboctahedra; corners with six equivalent Co(1)Ta4Co8 cuboctahedra; corners with eight Co(2,2,2)Ta4Co8 cuboctahedra; edges with two equivalent Ta(1)Co12 cuboctahedra; edges with four equivalent Ta(2)Co12 cuboctahedra; edges with four Co(1,1)Ta4Co8 cuboctahedra; edges with eight Co(2,2,2,2)Ta4Co8 cuboctahedra; faces with two equivalent Ta(1)Co12 cuboctahedra; faces with two equivalent Ta(2)Co12 cuboctahedra; faces with four Co(1,1)Ta4Co8 cuboctahedra; and faces with twelve Co(2,2,2,2)Ta4Co8 cuboctahedra. Both Co(1)-Ta(2) bond lengths are 2.59 Å. All Co(1)-Co(1,1) bond lengths are 2.55 Å. All Co(1)-Co(2,2,2,2) bond lengths are 2.50 Å. In the third Co site, Co(1) is bonded to two equivalent Ta(1); two equivalent Ta(2); four Co(1,1); and four Co(2,2) atoms to form CoTa4Co8 cuboctahedra that share corners with four equivalent Ta(2)Co12 cuboctahedra; corners with six equivalent Co(1)Ta4Co8 cuboctahedra; corners with eight Co(2,2,2)Ta4Co8 cuboctahedra; edges with two equivalent Ta(1)Co12 cuboctahedra; edges with four equivalent Ta(2)Co12 cuboctahedra; edges with four Co(1,1)Ta4Co8 cuboctahedra; edges with eight Co(2,2)Ta4Co8 cuboctahedra; faces with two equivalent Ta(1)Co12 cuboctahedra; faces with two equivalent Ta(2)Co12 cuboctahedra; faces with four Co(1,1)Ta4Co8 cuboctahedra; and faces with twelve Co(2,2,2,2)Ta4Co8 cuboctahedra. Both Co(1)-Ta(2) bond lengths are 2.59 Å. Both Co(1)-Co(1) bond lengths are 2.55 Å. All Co(1)-Co(2,2) bond lengths are 2.50 Å. In the fourth Co site, Co(1) is bonded to two equivalent Ta(1); two equivalent Ta(2); four Co(1,1); and four Co(2,2,2) atoms to form CoTa4Co8 cuboctahedra that share corners with four equivalent Ta(2)Co12 cuboctahedra; corners with six equivalent Co(1)Ta4Co8 cuboctahedra; corners with eight equivalent Co(2)Ta4Co8 cuboctahedra; edges with two equivalent Ta(1)Co12 cuboctahedra; edges with four equivalent Ta(2)Co12 cuboctahedra; edges with four Co(1,1)Ta4Co8 cuboctahedra; edges with eight Co(2,2,2)Ta4Co8 cuboctahedra; faces with two equivalent Ta(1)Co12 cuboctahedra; faces with two equivalent Ta(2)Co12 cuboctahedra; faces with four Co(1,1)Ta4Co8 cuboctahedra; and faces with twelve Co(2,2,2,2,2,2)Ta4Co8 cuboctahedra. Both Co(1)-Ta(2) bond lengths are 2.59 Å. All Co(1)-Co(2,2,2) bond lengths are 2.50 Å. In the fifth Co site, Co(2) is bonded to one Ta(1); three equivalent Ta(2); two Co(1,1); and six Co(2,2) atoms to form distorted CoTa4Co8 cuboctahedra that share corners with two equivalent Ta(1)Co12 cuboctahedra; corners with four Co(1,1)Ta4Co8 cuboctahedra; corners with nine Co(2,2)Ta4Co8 cuboctahedra; edges with two equivalent Ta(1)Co12 cuboctahedra; edges with four Co(1,1)Ta4Co8 cuboctahedra; edges with five equivalent Ta(2)Co12 cuboctahedra; edges with ten Co(2,2,2)Ta4Co8 cuboctahedra;  a faceface with one Ta(1)Co12 cuboctahedra; faces with three equivalent Ta(2)Co12 cuboctahedra; faces with six Co(1,1,1)Ta4Co8 cuboctahedra; and faces with nine Co(2,2)Ta4Co8 cuboctahedra. The Co(2)-Ta(1) bond length is 2.57 Å. Both Co(2)-Co(1,1) bond lengths are 2.50 Å. There are a spread of Co(2)-Co(2,2) bond distances ranging from 2.41-2.70 Å. In the sixth Co site, Co(2) is bonded to one Ta(1); three equivalent Ta(2); two Co(1,1); and six Co(2,2,2) atoms to form distorted CoTa4Co8 cuboctahedra that share corners with two equivalent Ta(1)Co12 cuboctahedra; corners with four Co(1,1)Ta4Co8 cuboctahedra; corners with nine Co(2,2)Ta4Co8 cuboctahedra; edges with two equivalent Ta(1)Co12 cuboctahedra; edges with four Co(1,1)Ta4Co8 cuboctahedra; edges with five equivalent Ta(2)Co12 cuboctahedra; edges with ten Co(2,2,2)Ta4Co8 cuboctahedra;  a faceface with one Ta(1)Co12 cuboctahedra; faces with three equivalent Ta(2)Co12 cuboctahedra; faces with six Co(1,1,1)Ta4Co8 cuboctahedra; and faces with nine Co(2,2,2)Ta4Co8 cuboctahedra. Both Co(2)-Co(1,1) bond lengths are 2.50 Å. There are a spread of Co(2)-Co(2,2) bond distances ranging from 2.41-2.70 Å. In the seventh Co site, Co(2) is bonded to one Ta(1); three equivalent Ta(2); two Co(1,1); and six Co(2,2) atoms to form distorted CoTa4Co8 cuboctahedra that share corners with two equivalent Ta(1)Co12 cuboctahedra; corners with four equivalent Co(1)Ta4Co8 cuboctahedra; corners with nine Co(2,2)Ta4Co8 cuboctahedra; edges with two equivalent Ta(1)Co12 cuboctahedra; edges with four Co(1,1)Ta4Co8 cuboctahedra; edges with five equivalent Ta(2)Co12 cuboctahedra; edges with ten Co(2,2,2)Ta4Co8 cuboctahedra;  a faceface with one Ta(1)Co12 cuboctahedra; faces with three equivalent Ta(2)Co12 cuboctahedra; faces with six Co(1,1,1,1)Ta4Co8 cuboctahedra; and faces with nine Co(2,2)Ta4Co8 cuboctahedra. In the eighth Co site, Co(1) is bonded to two equivalent Ta(1); two equivalent Ta(2); four Co(1,1); and four Co(2,2,2) atoms to form CoTa4Co8 cuboctahedra that share corners with four equivalent Ta(2)Co12 cuboctahedra; corners with six equivalent Co(1)Ta4Co8 cuboctahedra; corners with eight Co(2,2,2)Ta4Co8 cuboctahedra; edges with two equivalent Ta(1)Co12 cuboctahedra; edges with four equivalent Ta(2)Co12 cuboctahedra; edges with four Co(1,1)Ta4Co8 cuboctahedra; edges with eight Co(2,2,2)Ta4Co8 cuboctahedra; faces with two equivalent Ta(1)Co12 cuboctahedra; faces with two equivalent Ta(2)Co12 cuboctahedra; faces with four Co(1,1)Ta4Co8 cuboctahedra; and faces with twelve Co(2,2,2,2)Ta4Co8 cuboctahedra. Both Co(1)-Ta(1) bond lengths are 2.55 Å. All Co(1)-Co(1,1) bond lengths are 2.55 Å. Both Co(1)-Co(2) bond lengths are 2.50 Å. In the ninth Co site, Co(1) is bonded to two equivalent Ta(1); two equivalent Ta(2); four equivalent Co(1); and four Co(2,2,2,2) atoms to form CoTa4Co8 cuboctahedra that share corners with four equivalent Ta(2)Co12 cuboctahedra; corners with six equivalent Co(1)Ta4Co8 cuboctahedra; corners with eight Co(2,2)Ta4Co8 cuboctahedra; edges with two equivalent Ta(1)Co12 cuboctahedra; edges with four equivalent Ta(2)Co12 cuboctahedra; edges with four equivalent Co(1)Ta4Co8 cuboctahedra; edges with eight Co(2,2,2,2)Ta4Co8 cuboctahedra; faces with two equivalent Ta(1)Co12 cuboctahedra; faces with two equivalent Ta(2)Co12 cuboctahedra; faces with four equivalent Co(1)Ta4Co8 cuboctahedra; and faces with twelve Co(2,2,2,2,2)Ta4Co8 cuboctahedra. Both Co(1)-Ta(1) bond lengths are 2.55 Å. Both Co(1)-Co(2,2) bond lengths are 2.50 Å. In the tenth Co site, Co(2) is bonded to one Ta(1); three equivalent Ta(2); two Co(1,1); and six Co(2,2,2) atoms to form distorted CoTa4Co8 cuboctahedra that share corners with two equivalent Ta(1)Co12 cuboctahedra; corners with four equivalent Co(1)Ta4Co8 cuboctahedra; corners with nine Co(2,2)Ta4Co8 cuboctahedra; edges with two equivalent Ta(1)Co12 cuboctahedra; edges with four Co(1,1)Ta4Co8 cuboctahedra; edges with five equivalent Ta(2)Co12 cuboctahedra; edges with ten Co(2,2,2,2)Ta4Co8 cuboctahedra;  a faceface with one Ta(1)Co12 cuboctahedra; faces with three equivalent Ta(2)Co12 cuboctahedra; faces with six Co(1,1,1)Ta4Co8 cuboctahedra; and faces with nine Co(2,2,2)Ta4Co8 cuboctahedra. There is one shorter (2.55 Å) and two longer (2.56 Å) Co(2)-Ta(2) bond lengths. Both Co(2)-Co(1,1) bond lengths are 2.50 Å. There are a spread of Co(2)-Co(2,2,2) bond distances ranging from 2.41-2.70 Å. In the eleventh Co site, Co(2) is bonded to one Ta(1); three equivalent Ta(2); two Co(1,1); and six Co(2,2,2) atoms to form distorted CoTa4Co8 cuboctahedra that share corners with two equivalent Ta(1)Co12 cuboctahedra; corners with four Co(1,1)Ta4Co8 cuboctahedra; corners with nine Co(2,2)Ta4Co8 cuboctahedra; edges with two equivalent Ta(1)Co12 cuboctahedra; edges with four Co(1,1)Ta4Co8 cuboctahedra; edges with five equivalent Ta(2)Co12 cuboctahedra; edges with ten Co(2,2,2,2)Ta4Co8 cuboctahedra;  a faceface with one Ta(1)Co12 cuboctahedra; faces with three equivalent Ta(2)Co12 cuboctahedra; faces with six Co(1,1)Ta4Co8 cuboctahedra; and faces with nine Co(2,2,2)Ta4Co8 cuboctahedra. The Co(2)-Ta(1) bond length is 2.57 Å. There is one shorter (2.55 Å) and two longer (2.56 Å) Co(2)-Ta(2) bond lengths. The Co(2)-Co(1) bond length is 2.50 Å. There are a spread of Co(2)-Co(2,2) bond distances ranging from 2.41-2.70 Å. In the twelfth Co site, Co(2) is bonded to one Ta(1); three equivalent Ta(2); two Co(1,1); and six Co(2,2) atoms to form distorted CoTa4Co8 cuboctahedra that share corners with two equivalent Ta(1)Co12 cuboctahedra; corners with four Co(1,1)Ta4Co8 cuboctahedra; corners with nine Co(2,2)Ta4Co8 cuboctahedra; edges with two equivalent Ta(1)Co12 cuboctahedra; edges with four Co(1,1)Ta4Co8 cuboctahedra; edges with five equivalent Ta(2)Co12 cuboctahedra; edges with ten Co(2,2,2)Ta4Co8 cuboctahedra;  a faceface with one Ta(1)Co12 cuboctahedra; faces with three equivalent Ta(2)Co12 cuboctahedra; faces with six Co(1,1,1,1)Ta4Co8 cuboctahedra; and faces with nine Co(2,2,2)Ta4Co8 cuboctahedra. There is one shorter (2.55 Å) and two longer (2.56 Å) Co(2)-Ta(2) bond lengths. There are a spread of Co(2)-Co(2,2) bond distances ranging from 2.41-2.70 Å.