Nb3Co3C crystallizes in the cubic Fd-3m space group. Nb(1) is bonded in a 2-coordinate geometry to two equivalent Co(1), four equivalent Co(2), and two equivalent C(1) atoms. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to six equivalent Nb(1) and six equivalent Co(2) atoms to form CoNb6Co6 cuboctahedra that share edges with six equivalent C(1)Nb6 octahedra and faces with six equivalent Co(1)Nb6Co6 cuboctahedra. In the second Co site, Co(2) is bonded in a distorted q6 geometry to six equivalent Nb(1), three equivalent Co(1), and three equivalent Co(2) atoms. C(1) is bonded to six equivalent Nb(1) atoms to form CNb6 octahedra that share corners with six equivalent C(1)Nb6 octahedra and edges with six equivalent Co(1)Nb6Co6 cuboctahedra. The corner-sharing octahedral tilt angles are 46°.
Nb3Co3C crystallizes in the cubic Fd-3m space group. Nb(1) is bonded in a 2-coordinate geometry to two equivalent Co(1), four equivalent Co(2), and two equivalent C(1) atoms. Both Nb(1)-Co(1) bond lengths are 2.83 Å. There are two shorter (2.79 Å) and two longer (2.82 Å) Nb(1)-Co(2) bond lengths. Both Nb(1)-C(1) bond lengths are 2.18 Å. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to six equivalent Nb(1) and six equivalent Co(2) atoms to form CoNb6Co6 cuboctahedra that share edges with six equivalent C(1)Nb6 octahedra and faces with six equivalent Co(1)Nb6Co6 cuboctahedra. All Co(1)-Co(2) bond lengths are 2.42 Å. In the second Co site, Co(2) is bonded in a distorted q6 geometry to six equivalent Nb(1), three equivalent Co(1), and three equivalent Co(2) atoms. All Co(2)-Co(2) bond lengths are 2.48 Å. C(1) is bonded to six equivalent Nb(1) atoms to form CNb6 octahedra that share corners with six equivalent C(1)Nb6 octahedra and edges with six equivalent Co(1)Nb6Co6 cuboctahedra. The corner-sharing octahedral tilt angles are 46°.