Ta2(Co7B2)3 crystallizes in the cubic Fm-3m space group. Ta(1) is bonded in a distorted tetrahedral geometry to four equivalent Co(2) atoms. There are three inequivalent Co sites. In the first Co site, Co(1) is bonded in a cuboctahedral geometry to twelve equivalent Co(3) atoms. In the second Co site, Co(2) is bonded to one Ta(1) and three equivalent B(1) atoms to form a mixture of corner and edge-sharing CoTaB3 tetrahedra. In the third Co site, Co(3) is bonded in a distorted bent 150 degrees geometry to one Co(1) and two equivalent B(1) atoms. B(1) is bonded in a 8-coordinate geometry to four equivalent Co(2) and four equivalent Co(3) atoms.
Ta2(Co7B2)3 crystallizes in the cubic Fm-3m space group. Ta(1) is bonded in a distorted tetrahedral geometry to four equivalent Co(2) atoms. All Ta(1)-Co(2) bond lengths are 2.43 Å. There are three inequivalent Co sites. In the first Co site, Co(1) is bonded in a cuboctahedral geometry to twelve equivalent Co(3) atoms. All Co(1)-Co(3) bond lengths are 2.51 Å. In the second Co site, Co(2) is bonded to one Ta(1) and three equivalent B(1) atoms to form a mixture of corner and edge-sharing CoTaB3 tetrahedra. All Co(2)-B(1) bond lengths are 2.07 Å. In the third Co site, Co(3) is bonded in a distorted bent 150 degrees geometry to one Co(1) and two equivalent B(1) atoms. Both Co(3)-B(1) bond lengths are 2.09 Å. B(1) is bonded in a 8-coordinate geometry to four equivalent Co(2) and four equivalent Co(3) atoms.