NbCo3 crystallizes in the hexagonal P6_3mc space group. There are three inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 16-coordinate geometry to three equivalent Nb(3), one Co(3), three equivalent Co(1), three equivalent Co(5), and six equivalent Co(2) atoms. In the second Nb site, Nb(2) is bonded in a 16-coordinate geometry to one Nb(3), three equivalent Co(2), three equivalent Co(3), three equivalent Co(4), and six equivalent Co(1) atoms. In the third Nb site, Nb(3) is bonded in a 16-coordinate geometry to one Nb(2), three equivalent Nb(1), three equivalent Co(2), three equivalent Co(5), and six equivalent Co(1) atoms. There are five inequivalent Co sites. In the first Co site, Co(1) is bonded to one Nb(1), two equivalent Nb(2), two equivalent Nb(3), one Co(3), one Co(4), one Co(5), and four equivalent Co(1) atoms to form CoNb5Co7 cuboctahedra that share corners with two equivalent Co(4)Nb3Co9 cuboctahedra, corners with two equivalent Co(5)Nb6Co6 cuboctahedra, corners with four equivalent Co(1)Nb5Co7 cuboctahedra, corners with ten equivalent Co(2)Nb4Co8 cuboctahedra, edges with two equivalent Co(1)Nb5Co7 cuboctahedra, edges with four equivalent Co(2)Nb4Co8 cuboctahedra, faces with three equivalent Co(4)Nb3Co9 cuboctahedra, faces with three equivalent Co(5)Nb6Co6 cuboctahedra, faces with four equivalent Co(2)Nb4Co8 cuboctahedra, and faces with eight equivalent Co(1)Nb5Co7 cuboctahedra. In the second Co site, Co(2) is bonded to one Nb(2), one Nb(3), two equivalent Nb(1), one Co(4), one Co(5), two equivalent Co(3), and four equivalent Co(2) atoms to form distorted CoNb4Co8 cuboctahedra that share corners with two equivalent Co(4)Nb3Co9 cuboctahedra, corners with two equivalent Co(5)Nb6Co6 cuboctahedra, corners with four equivalent Co(2)Nb4Co8 cuboctahedra, corners with ten equivalent Co(1)Nb5Co7 cuboctahedra, edges with two equivalent Co(2)Nb4Co8 cuboctahedra, edges with four equivalent Co(1)Nb5Co7 cuboctahedra, faces with three equivalent Co(4)Nb3Co9 cuboctahedra, faces with three equivalent Co(5)Nb6Co6 cuboctahedra, faces with four equivalent Co(1)Nb5Co7 cuboctahedra, and faces with eight equivalent Co(2)Nb4Co8 cuboctahedra. In the third Co site, Co(3) is bonded in a 16-coordinate geometry to one Nb(1), three equivalent Nb(2), three equivalent Co(1), three equivalent Co(4), and six equivalent Co(2) atoms. In the fourth Co site, Co(4) is bonded to three equivalent Nb(2), three equivalent Co(1), three equivalent Co(2), and three equivalent Co(3) atoms to form CoNb3Co9 cuboctahedra that share corners with three equivalent Co(5)Nb6Co6 cuboctahedra, corners with six equivalent Co(2)Nb4Co8 cuboctahedra, corners with six equivalent Co(1)Nb5Co7 cuboctahedra, edges with six equivalent Co(4)Nb3Co9 cuboctahedra,  a faceface with one Co(5)Nb6Co6 cuboctahedra, faces with nine equivalent Co(2)Nb4Co8 cuboctahedra, and faces with nine equivalent Co(1)Nb5Co7 cuboctahedra. In the fifth Co site, Co(5) is bonded to three equivalent Nb(1), three equivalent Nb(3), three equivalent Co(1), and three equivalent Co(2) atoms to form CoNb6Co6 cuboctahedra that share corners with three equivalent Co(4)Nb3Co9 cuboctahedra, corners with six equivalent Co(2)Nb4Co8 cuboctahedra, corners with six equivalent Co(1)Nb5Co7 cuboctahedra, edges with six equivalent Co(5)Nb6Co6 cuboctahedra,  a faceface with one Co(4)Nb3Co9 cuboctahedra, faces with nine equivalent Co(2)Nb4Co8 cuboctahedra, and faces with nine equivalent Co(1)Nb5Co7 cuboctahedra.
NbCo3 crystallizes in the hexagonal P6_3mc space group. There are three inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 16-coordinate geometry to three equivalent Nb(3), one Co(3), three equivalent Co(1), three equivalent Co(5), and six equivalent Co(2) atoms. All Nb(1)-Nb(3) bond lengths are 2.99 Å. The Nb(1)-Co(3) bond length is 2.77 Å. All Nb(1)-Co(1) bond lengths are 2.97 Å. All Nb(1)-Co(5) bond lengths are 2.81 Å. All Nb(1)-Co(2) bond lengths are 2.67 Å. In the second Nb site, Nb(2) is bonded in a 16-coordinate geometry to one Nb(3), three equivalent Co(2), three equivalent Co(3), three equivalent Co(4), and six equivalent Co(1) atoms. The Nb(2)-Nb(3) bond length is 2.94 Å. All Nb(2)-Co(2) bond lengths are 2.68 Å. All Nb(2)-Co(3) bond lengths are 2.84 Å. All Nb(2)-Co(4) bond lengths are 2.76 Å. All Nb(2)-Co(1) bond lengths are 2.81 Å. In the third Nb site, Nb(3) is bonded in a 16-coordinate geometry to one Nb(2), three equivalent Nb(1), three equivalent Co(2), three equivalent Co(5), and six equivalent Co(1) atoms. All Nb(3)-Co(2) bond lengths are 2.83 Å. All Nb(3)-Co(5) bond lengths are 2.77 Å. All Nb(3)-Co(1) bond lengths are 2.75 Å. There are five inequivalent Co sites. In the first Co site, Co(1) is bonded to one Nb(1), two equivalent Nb(2), two equivalent Nb(3), one Co(3), one Co(4), one Co(5), and four equivalent Co(1) atoms to form CoNb5Co7 cuboctahedra that share corners with two equivalent Co(4)Nb3Co9 cuboctahedra, corners with two equivalent Co(5)Nb6Co6 cuboctahedra, corners with four equivalent Co(1)Nb5Co7 cuboctahedra, corners with ten equivalent Co(2)Nb4Co8 cuboctahedra, edges with two equivalent Co(1)Nb5Co7 cuboctahedra, edges with four equivalent Co(2)Nb4Co8 cuboctahedra, faces with three equivalent Co(4)Nb3Co9 cuboctahedra, faces with three equivalent Co(5)Nb6Co6 cuboctahedra, faces with four equivalent Co(2)Nb4Co8 cuboctahedra, and faces with eight equivalent Co(1)Nb5Co7 cuboctahedra. The Co(1)-Co(3) bond length is 2.70 Å. The Co(1)-Co(4) bond length is 2.38 Å. The Co(1)-Co(5) bond length is 2.37 Å. All Co(1)-Co(1) bond lengths are 2.36 Å. In the second Co site, Co(2) is bonded to one Nb(2), one Nb(3), two equivalent Nb(1), one Co(4), one Co(5), two equivalent Co(3), and four equivalent Co(2) atoms to form distorted CoNb4Co8 cuboctahedra that share corners with two equivalent Co(4)Nb3Co9 cuboctahedra, corners with two equivalent Co(5)Nb6Co6 cuboctahedra, corners with four equivalent Co(2)Nb4Co8 cuboctahedra, corners with ten equivalent Co(1)Nb5Co7 cuboctahedra, edges with two equivalent Co(2)Nb4Co8 cuboctahedra, edges with four equivalent Co(1)Nb5Co7 cuboctahedra, faces with three equivalent Co(4)Nb3Co9 cuboctahedra, faces with three equivalent Co(5)Nb6Co6 cuboctahedra, faces with four equivalent Co(1)Nb5Co7 cuboctahedra, and faces with eight equivalent Co(2)Nb4Co8 cuboctahedra. The Co(2)-Co(4) bond length is 2.34 Å. The Co(2)-Co(5) bond length is 2.40 Å. Both Co(2)-Co(3) bond lengths are 2.80 Å. There are two shorter (2.33 Å) and two longer (2.39 Å) Co(2)-Co(2) bond lengths. In the third Co site, Co(3) is bonded in a 16-coordinate geometry to one Nb(1), three equivalent Nb(2), three equivalent Co(1), three equivalent Co(4), and six equivalent Co(2) atoms. All Co(3)-Co(4) bond lengths are 2.75 Å. In the fourth Co site, Co(4) is bonded to three equivalent Nb(2), three equivalent Co(1), three equivalent Co(2), and three equivalent Co(3) atoms to form CoNb3Co9 cuboctahedra that share corners with three equivalent Co(5)Nb6Co6 cuboctahedra, corners with six equivalent Co(2)Nb4Co8 cuboctahedra, corners with six equivalent Co(1)Nb5Co7 cuboctahedra, edges with six equivalent Co(4)Nb3Co9 cuboctahedra,  a faceface with one Co(5)Nb6Co6 cuboctahedra, faces with nine equivalent Co(2)Nb4Co8 cuboctahedra, and faces with nine equivalent Co(1)Nb5Co7 cuboctahedra. In the fifth Co site, Co(5) is bonded to three equivalent Nb(1), three equivalent Nb(3), three equivalent Co(1), and three equivalent Co(2) atoms to form CoNb6Co6 cuboctahedra that share corners with three equivalent Co(4)Nb3Co9 cuboctahedra, corners with six equivalent Co(2)Nb4Co8 cuboctahedra, corners with six equivalent Co(1)Nb5Co7 cuboctahedra, edges with six equivalent Co(5)Nb6Co6 cuboctahedra,  a faceface with one Co(4)Nb3Co9 cuboctahedra, faces with nine equivalent Co(2)Nb4Co8 cuboctahedra, and faces with nine equivalent Co(1)Nb5Co7 cuboctahedra.