HfCo3 is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. Hf(1) is bonded to twelve Co(1,1,1) atoms to form HfCo12 cuboctahedra that share corners with six equivalent Hf(1)Co12 cuboctahedra; corners with twelve Co(1,1)Hf4Co8 cuboctahedra; edges with eighteen Co(1,1,1)Hf4Co8 cuboctahedra; faces with eight equivalent Hf(1)Co12 cuboctahedra; and faces with twelve Co(1,1,1)Hf4Co8 cuboctahedra. There are three inequivalent Co sites. In the first Co site, Co(1) is bonded to four equivalent Hf(1) and eight Co(1,1,1) atoms to form distorted CoHf4Co8 cuboctahedra that share corners with four equivalent Hf(1)Co12 cuboctahedra; corners with fourteen Co(1,1)Hf4Co8 cuboctahedra; edges with six equivalent Hf(1)Co12 cuboctahedra; edges with twelve Co(1,1,1)Hf4Co8 cuboctahedra; faces with four equivalent Hf(1)Co12 cuboctahedra; and faces with sixteen Co(1,1,1)Hf4Co8 cuboctahedra. In the second Co site, Co(1) is bonded to four equivalent Hf(1) and eight Co(1,1) atoms to form distorted CoHf4Co8 cuboctahedra that share corners with four equivalent Hf(1)Co12 cuboctahedra; corners with fourteen Co(1,1)Hf4Co8 cuboctahedra; edges with six equivalent Hf(1)Co12 cuboctahedra; edges with twelve Co(1,1)Hf4Co8 cuboctahedra; faces with four equivalent Hf(1)Co12 cuboctahedra; and faces with sixteen Co(1,1,1)Hf4Co8 cuboctahedra. In the third Co site, Co(1) is bonded to four equivalent Hf(1) and eight Co(1,1) atoms to form distorted CoHf4Co8 cuboctahedra that share corners with four equivalent Hf(1)Co12 cuboctahedra; corners with fourteen Co(1,1)Hf4Co8 cuboctahedra; edges with six equivalent Hf(1)Co12 cuboctahedra; edges with twelve Co(1,1)Hf4Co8 cuboctahedra; faces with four equivalent Hf(1)Co12 cuboctahedra; and faces with sixteen Co(1,1,1)Hf4Co8 cuboctahedra.
HfCo3 is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. Hf(1) is bonded to twelve Co(1,1,1) atoms to form HfCo12 cuboctahedra that share corners with six equivalent Hf(1)Co12 cuboctahedra; corners with twelve Co(1,1)Hf4Co8 cuboctahedra; edges with eighteen Co(1,1,1)Hf4Co8 cuboctahedra; faces with eight equivalent Hf(1)Co12 cuboctahedra; and faces with twelve Co(1,1,1)Hf4Co8 cuboctahedra. There are six shorter (2.67 Å) and six longer (2.69 Å) Hf(1)-Co(1,1,1) bond lengths. There are three inequivalent Co sites. In the first Co site, Co(1) is bonded to four equivalent Hf(1) and eight Co(1,1,1) atoms to form distorted CoHf4Co8 cuboctahedra that share corners with four equivalent Hf(1)Co12 cuboctahedra; corners with fourteen Co(1,1)Hf4Co8 cuboctahedra; edges with six equivalent Hf(1)Co12 cuboctahedra; edges with twelve Co(1,1,1)Hf4Co8 cuboctahedra; faces with four equivalent Hf(1)Co12 cuboctahedra; and faces with sixteen Co(1,1,1)Hf4Co8 cuboctahedra. There are a spread of Co(1)-Co(1,1,1) bond distances ranging from 2.48-2.85 Å. In the second Co site, Co(1) is bonded to four equivalent Hf(1) and eight Co(1,1) atoms to form distorted CoHf4Co8 cuboctahedra that share corners with four equivalent Hf(1)Co12 cuboctahedra; corners with fourteen Co(1,1)Hf4Co8 cuboctahedra; edges with six equivalent Hf(1)Co12 cuboctahedra; edges with twelve Co(1,1)Hf4Co8 cuboctahedra; faces with four equivalent Hf(1)Co12 cuboctahedra; and faces with sixteen Co(1,1,1)Hf4Co8 cuboctahedra. Both Co(1)-Co(1) bond lengths are 2.56 Å. In the third Co site, Co(1) is bonded to four equivalent Hf(1) and eight Co(1,1) atoms to form distorted CoHf4Co8 cuboctahedra that share corners with four equivalent Hf(1)Co12 cuboctahedra; corners with fourteen Co(1,1)Hf4Co8 cuboctahedra; edges with six equivalent Hf(1)Co12 cuboctahedra; edges with twelve Co(1,1)Hf4Co8 cuboctahedra; faces with four equivalent Hf(1)Co12 cuboctahedra; and faces with sixteen Co(1,1,1)Hf4Co8 cuboctahedra.