DOE OSTI2020
Co2NiAl is beta Cu3Ti-derived structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Co is bonded to four equivalent Co, four equivalent Ni, and four equivalent Al atoms to form CoAl4Co4Ni4 cuboctahedra that share corners with twelve equivalent CoAl4Co4Ni4 cuboctahedra, edges with eight equivalent CoAl4Co4Ni4 cuboctahedra, edges with eight equivalent NiAl4Co8 cuboctahedra, edges with eight equivalent AlCo8Ni4 cuboctahedra, faces with four equivalent NiAl4Co8 cuboctahedra, faces with four equivalent AlCo8Ni4 cuboctahedra, and faces with ten equivalent CoAl4Co4Ni4 cuboctahedra. All Co–Co bond lengths are 2.52 Å. All Co–Ni bond lengths are 2.52 Å. All Co–Al bond lengths are 2.52 Å. Ni is bonded to eight equivalent Co and four equivalent Al atoms to form NiAl4Co8 cuboctahedra that share corners with four equivalent NiAl4Co8 cuboctahedra, corners with eight equivalent AlCo8Ni4 cuboctahedra, edges with eight equivalent NiAl4Co8 cuboctahedra, edges with sixteen equivalent CoAl4Co4Ni4 cuboctahedra, faces with four equivalent NiAl4Co8 cuboctahedra, faces with six equivalent AlCo8Ni4 cuboctahedra, and faces with eight equivalent CoAl4Co4Ni4 cuboctahedra. All Ni–Al bond lengths are 2.52 Å. Al is bonded to eight equivalent Co and four equivalent Ni atoms to form AlCo8Ni4 cuboctahedra that share corners with four equivalent AlCo8Ni4 cuboctahedra, corners with eight equivalent NiAl4Co8 cuboctahedra, edges with eight equivalent AlCo8Ni4 cuboctahedra, edges with sixteen equivalent CoAl4Co4Ni4 cuboctahedra, faces with four equivalent AlCo8Ni4 cuboctahedra, faces with six equivalent NiAl4Co8 cuboctahedra, and faces with eight equivalent CoAl4Co4Ni4 cuboctahedra.