DOE OSTI2020
Co3Ti is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Ti is bonded to twelve Co atoms to form TiCo12 cuboctahedra that share corners with six equivalent TiCo12 cuboctahedra, corners with twelve CoTi4Co8 cuboctahedra, edges with eighteen CoTi4Co8 cuboctahedra, faces with eight equivalent TiCo12 cuboctahedra, and faces with twelve CoTi4Co8 cuboctahedra. There are six shorter (2.56 Å) and six longer (2.57 Å) Ti–Co bond lengths. There are three inequivalent Co sites. In the first Co site, Co is bonded to four equivalent Ti and eight Co atoms to form distorted CoTi4Co8 cuboctahedra that share corners with four equivalent TiCo12 cuboctahedra, corners with fourteen CoTi4Co8 cuboctahedra, edges with six equivalent TiCo12 cuboctahedra, edges with twelve CoTi4Co8 cuboctahedra, faces with four equivalent TiCo12 cuboctahedra, and faces with sixteen CoTi4Co8 cuboctahedra. There are a spread of Co–Co bond distances ranging from 2.50–2.63 Å. In the second Co site, Co is bonded to four equivalent Ti and eight Co atoms to form distorted CoTi4Co8 cuboctahedra that share corners with four equivalent TiCo12 cuboctahedra, corners with fourteen CoTi4Co8 cuboctahedra, edges with six equivalent TiCo12 cuboctahedra, edges with twelve CoTi4Co8 cuboctahedra, faces with four equivalent TiCo12 cuboctahedra, and faces with sixteen CoTi4Co8 cuboctahedra. There are a spread of Co–Co bond distances ranging from 2.50–2.63 Å. In the third Co site, Co is bonded to four equivalent Ti and eight Co atoms to form distorted CoTi4Co8 cuboctahedra that share corners with four equivalent TiCo12 cuboctahedra, corners with fourteen CoTi4Co8 cuboctahedra, edges with six equivalent TiCo12 cuboctahedra, edges with twelve CoTi4Co8 cuboctahedra, faces with four equivalent TiCo12 cuboctahedra, and faces with sixteen CoTi4Co8 cuboctahedra.