MgCo3 is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. Mg(1) is bonded to twelve Co(1,1) atoms to form MgCo12 cuboctahedra that share corners with six equivalent Mg(1)Co12 cuboctahedra; corners with twelve Co(1,1)Mg4Co8 cuboctahedra; edges with eighteen Co(1,1)Mg4Co8 cuboctahedra; faces with eight equivalent Mg(1)Co12 cuboctahedra; and faces with twelve Co(1,1)Mg4Co8 cuboctahedra. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to four equivalent Mg(1) and eight Co(1,1) atoms to form distorted CoMg4Co8 cuboctahedra that share corners with four equivalent Mg(1)Co12 cuboctahedra; corners with fourteen Co(1,1)Mg4Co8 cuboctahedra; edges with six equivalent Mg(1)Co12 cuboctahedra; edges with twelve Co(1,1)Mg4Co8 cuboctahedra; faces with four equivalent Mg(1)Co12 cuboctahedra; and faces with sixteen Co(1,1)Mg4Co8 cuboctahedra. In the second Co site, Co(1) is bonded to four equivalent Mg(1) and eight equivalent Co(1) atoms to form distorted CoMg4Co8 cuboctahedra that share corners with four equivalent Mg(1)Co12 cuboctahedra; corners with fourteen Co(1,1)Mg4Co8 cuboctahedra; edges with six equivalent Mg(1)Co12 cuboctahedra; edges with twelve equivalent Co(1)Mg4Co8 cuboctahedra; faces with four equivalent Mg(1)Co12 cuboctahedra; and faces with sixteen Co(1,1)Mg4Co8 cuboctahedra.
MgCo3 is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. Mg(1) is bonded to twelve Co(1,1) atoms to form MgCo12 cuboctahedra that share corners with six equivalent Mg(1)Co12 cuboctahedra; corners with twelve Co(1,1)Mg4Co8 cuboctahedra; edges with eighteen Co(1,1)Mg4Co8 cuboctahedra; faces with eight equivalent Mg(1)Co12 cuboctahedra; and faces with twelve Co(1,1)Mg4Co8 cuboctahedra. There are six shorter (2.61 Å) and six longer (2.62 Å) Mg(1)-Co(1,1) bond lengths. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to four equivalent Mg(1) and eight Co(1,1) atoms to form distorted CoMg4Co8 cuboctahedra that share corners with four equivalent Mg(1)Co12 cuboctahedra; corners with fourteen Co(1,1)Mg4Co8 cuboctahedra; edges with six equivalent Mg(1)Co12 cuboctahedra; edges with twelve Co(1,1)Mg4Co8 cuboctahedra; faces with four equivalent Mg(1)Co12 cuboctahedra; and faces with sixteen Co(1,1)Mg4Co8 cuboctahedra. There are a spread of Co(1)-Co(1,1) bond distances ranging from 2.49-2.72 Å. In the second Co site, Co(1) is bonded to four equivalent Mg(1) and eight equivalent Co(1) atoms to form distorted CoMg4Co8 cuboctahedra that share corners with four equivalent Mg(1)Co12 cuboctahedra; corners with fourteen Co(1,1)Mg4Co8 cuboctahedra; edges with six equivalent Mg(1)Co12 cuboctahedra; edges with twelve equivalent Co(1)Mg4Co8 cuboctahedra; faces with four equivalent Mg(1)Co12 cuboctahedra; and faces with sixteen Co(1,1)Mg4Co8 cuboctahedra.