Materials Data on Fe3Cu by Materials Project
Fe3Cu is alpha La-derived structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are two inequivalent Fe sites. In the first Fe site, Fe is bonded to eight Fe and four equivalent Cu atoms to form FeFe8Cu4 cuboctahedra that share corners with twelve equivalent FeFe8Cu4 cuboctahedra, edges with eight equivalent CuFe12 cuboctahedra, edges with sixteen FeFe8Cu4 cuboctahedra, faces with four equivalent CuFe12 cuboctahedra, and faces with fourteen FeFe8Cu4 cuboctahedra. There are four shorter (2.55 Å) and four longer (2.56 Å) Fe–Fe bond lengths. All Fe–Cu bond lengths are 2.55 Å. In the second Fe site, Fe is bonded to eight equivalent Fe and four equivalent Cu atoms to form FeFe8Cu4 cuboctahedra that share corners with four equivalent FeFe8Cu4 cuboctahedra, corners with eight equivalent CuFe12 cuboctahedra, edges with twenty-four FeFe8Cu4 cuboctahedra, faces with six equivalent CuFe12 cuboctahedra, and faces with twelve FeFe8Cu4 cuboctahedra. All Fe–Cu bond lengths are 2.56 Å. Cu is bonded to twelve Fe atoms to form CuFe12 cuboctahedra that share corners with four equivalent CuFe12 cuboctahedra, corners with eight equivalent FeFe8Cu4 cuboctahedra, edges with eight equivalent CuFe12 cuboctahedra, edges with sixteen equivalent FeFe8Cu4 cuboctahedra, faces with four equivalent CuFe12 cuboctahedra, and faces with fourteen FeFe8Cu4 cuboctahedra.