CoMo is Frank-Kasper $\mu$ Phase-like structured and crystallizes in the trigonal R-3m space group. There are seven inequivalent Mo sites. In the first Mo site, Mo(1) is bonded in a 16-coordinate geometry to one Mo(3), three equivalent Mo(1), three equivalent Co(3), and nine equivalent Co(2) atoms. In the second Mo site, Mo(2) is bonded in a 16-coordinate geometry to one Mo(4), three equivalent Mo(2), three equivalent Mo(7), and nine equivalent Co(1) atoms. In the third Mo site, Mo(3) is bonded in a 14-coordinate geometry to one Mo(1), one Mo(4), three equivalent Mo(5), three equivalent Mo(6), and six equivalent Co(2) atoms. In the fourth Mo site, Mo(4) is bonded in a 14-coordinate geometry to one Mo(2), one Mo(3), three equivalent Mo(5), three equivalent Mo(6), and six equivalent Co(1) atoms. In the fifth Mo site, Mo(5) is bonded in a 6-coordinate geometry to three equivalent Mo(3), three equivalent Mo(4), three equivalent Co(1), and three equivalent Co(2) atoms. In the sixth Mo site, Mo(6) is bonded in a 6-coordinate geometry to three equivalent Mo(3), three equivalent Mo(4), three equivalent Co(1), and three equivalent Co(2) atoms. In the seventh Mo site, Mo(7) is bonded to six equivalent Mo(2) and six equivalent Co(1) atoms to form distorted MoCo6Mo6 cuboctahedra that share corners with twelve equivalent Co(1)Co4Mo8 cuboctahedra, edges with six equivalent Mo(7)Co6Mo6 cuboctahedra, and faces with eighteen equivalent Co(1)Co4Mo8 cuboctahedra. There are three inequivalent Co sites. In the first Co site, Co(1) is bonded to one Mo(5), one Mo(6), one Mo(7), two equivalent Mo(4), three equivalent Mo(2), and four equivalent Co(1) atoms to form distorted CoCo4Mo8 cuboctahedra that share corners with two equivalent Mo(7)Co6Mo6 cuboctahedra, corners with four equivalent Co(2)Co5Mo7 cuboctahedra, corners with nine equivalent Co(1)Co4Mo8 cuboctahedra,  an edgeedge with one Co(2)Co5Mo7 cuboctahedra, edges with four equivalent Co(1)Co4Mo8 cuboctahedra, faces with three equivalent Mo(7)Co6Mo6 cuboctahedra, and faces with ten equivalent Co(1)Co4Mo8 cuboctahedra. In the second Co site, Co(2) is bonded to one Mo(5), one Mo(6), two equivalent Mo(3), three equivalent Mo(1), one Co(3), and four equivalent Co(2) atoms to form CoCo5Mo7 cuboctahedra that share corners with two equivalent Co(3)Co6Mo6 cuboctahedra, corners with four equivalent Co(1)Co4Mo8 cuboctahedra, corners with nine equivalent Co(2)Co5Mo7 cuboctahedra,  an edgeedge with one Co(1)Co4Mo8 cuboctahedra, edges with four equivalent Co(2)Co5Mo7 cuboctahedra, faces with three equivalent Co(3)Co6Mo6 cuboctahedra, and faces with ten equivalent Co(2)Co5Mo7 cuboctahedra. In the third Co site, Co(3) is bonded to six equivalent Mo(1) and six equivalent Co(2) atoms to form CoCo6Mo6 cuboctahedra that share corners with twelve equivalent Co(2)Co5Mo7 cuboctahedra, edges with six equivalent Co(3)Co6Mo6 cuboctahedra, and faces with eighteen equivalent Co(2)Co5Mo7 cuboctahedra.
CoMo is Frank-Kasper $\mu$ Phase-like structured and crystallizes in the trigonal R-3m space group. There are seven inequivalent Mo sites. In the first Mo site, Mo(1) is bonded in a 16-coordinate geometry to one Mo(3), three equivalent Mo(1), three equivalent Co(3), and nine equivalent Co(2) atoms. The Mo(1)-Mo(3) bond length is 2.65 Å. All Mo(1)-Mo(1) bond lengths are 2.85 Å. All Mo(1)-Co(3) bond lengths are 2.78 Å. There are three shorter (2.70 Å) and six longer (2.88 Å) Mo(1)-Co(2) bond lengths. In the second Mo site, Mo(2) is bonded in a 16-coordinate geometry to one Mo(4), three equivalent Mo(2), three equivalent Mo(7), and nine equivalent Co(1) atoms. The Mo(2)-Mo(4) bond length is 2.69 Å. All Mo(2)-Mo(2) bond lengths are 2.85 Å. All Mo(2)-Mo(7) bond lengths are 2.78 Å. There are three shorter (2.75 Å) and six longer (2.91 Å) Mo(2)-Co(1) bond lengths. In the third Mo site, Mo(3) is bonded in a 14-coordinate geometry to one Mo(1), one Mo(4), three equivalent Mo(5), three equivalent Mo(6), and six equivalent Co(2) atoms. The Mo(3)-Mo(4) bond length is 2.52 Å. All Mo(3)-Mo(5) bond lengths are 3.01 Å. All Mo(3)-Mo(6) bond lengths are 3.04 Å. All Mo(3)-Co(2) bond lengths are 2.60 Å. In the fourth Mo site, Mo(4) is bonded in a 14-coordinate geometry to one Mo(2), one Mo(3), three equivalent Mo(5), three equivalent Mo(6), and six equivalent Co(1) atoms. All Mo(4)-Mo(5) bond lengths are 3.05 Å. All Mo(4)-Mo(6) bond lengths are 3.02 Å. All Mo(4)-Co(1) bond lengths are 2.60 Å. In the fifth Mo site, Mo(5) is bonded in a 6-coordinate geometry to three equivalent Mo(3), three equivalent Mo(4), three equivalent Co(1), and three equivalent Co(2) atoms. All Mo(5)-Co(1) bond lengths are 2.69 Å. All Mo(5)-Co(2) bond lengths are 2.63 Å. In the sixth Mo site, Mo(6) is bonded in a 6-coordinate geometry to three equivalent Mo(3), three equivalent Mo(4), three equivalent Co(1), and three equivalent Co(2) atoms. All Mo(6)-Co(1) bond lengths are 2.65 Å. All Mo(6)-Co(2) bond lengths are 2.69 Å. In the seventh Mo site, Mo(7) is bonded to six equivalent Mo(2) and six equivalent Co(1) atoms to form distorted MoCo6Mo6 cuboctahedra that share corners with twelve equivalent Co(1)Co4Mo8 cuboctahedra, edges with six equivalent Mo(7)Co6Mo6 cuboctahedra, and faces with eighteen equivalent Co(1)Co4Mo8 cuboctahedra. All Mo(7)-Co(1) bond lengths are 2.47 Å. There are three inequivalent Co sites. In the first Co site, Co(1) is bonded to one Mo(5), one Mo(6), one Mo(7), two equivalent Mo(4), three equivalent Mo(2), and four equivalent Co(1) atoms to form distorted CoCo4Mo8 cuboctahedra that share corners with two equivalent Mo(7)Co6Mo6 cuboctahedra, corners with four equivalent Co(2)Co5Mo7 cuboctahedra, corners with nine equivalent Co(1)Co4Mo8 cuboctahedra,  an edgeedge with one Co(2)Co5Mo7 cuboctahedra, edges with four equivalent Co(1)Co4Mo8 cuboctahedra, faces with three equivalent Mo(7)Co6Mo6 cuboctahedra, and faces with ten equivalent Co(1)Co4Mo8 cuboctahedra. There are two shorter (2.34 Å) and two longer (2.43 Å) Co(1)-Co(1) bond lengths. In the second Co site, Co(2) is bonded to one Mo(5), one Mo(6), two equivalent Mo(3), three equivalent Mo(1), one Co(3), and four equivalent Co(2) atoms to form CoCo5Mo7 cuboctahedra that share corners with two equivalent Co(3)Co6Mo6 cuboctahedra, corners with four equivalent Co(1)Co4Mo8 cuboctahedra, corners with nine equivalent Co(2)Co5Mo7 cuboctahedra,  an edgeedge with one Co(1)Co4Mo8 cuboctahedra, edges with four equivalent Co(2)Co5Mo7 cuboctahedra, faces with three equivalent Co(3)Co6Mo6 cuboctahedra, and faces with ten equivalent Co(2)Co5Mo7 cuboctahedra. The Co(2)-Co(3) bond length is 2.41 Å. There are two shorter (2.38 Å) and two longer (2.40 Å) Co(2)-Co(2) bond lengths. In the third Co site, Co(3) is bonded to six equivalent Mo(1) and six equivalent Co(2) atoms to form CoCo6Mo6 cuboctahedra that share corners with twelve equivalent Co(2)Co5Mo7 cuboctahedra, edges with six equivalent Co(3)Co6Mo6 cuboctahedra, and faces with eighteen equivalent Co(2)Co5Mo7 cuboctahedra.