Materials Data on Al3Cr by Materials Project
CrAl3 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Cr is bonded to twelve Al atoms to form CrAl12 cuboctahedra that share corners with four equivalent CrAl12 cuboctahedra, corners with eight equivalent AlAl8Cr4 cuboctahedra, edges with eight equivalent CrAl12 cuboctahedra, edges with sixteen equivalent AlAl8Cr4 cuboctahedra, faces with four equivalent CrAl12 cuboctahedra, and faces with fourteen AlAl8Cr4 cuboctahedra. There are four shorter (2.67 Å) and eight longer (2.77 Å) Cr–Al bond lengths. There are two inequivalent Al sites. In the first Al site, Al is bonded to four equivalent Cr and eight Al atoms to form AlAl8Cr4 cuboctahedra that share corners with twelve equivalent AlAl8Cr4 cuboctahedra, edges with eight equivalent CrAl12 cuboctahedra, edges with sixteen AlAl8Cr4 cuboctahedra, faces with four equivalent CrAl12 cuboctahedra, and faces with fourteen AlAl8Cr4 cuboctahedra. There are four shorter (2.67 Å) and four longer (2.77 Å) Al–Al bond lengths. In the second Al site, Al is bonded to four equivalent Cr and eight equivalent Al atoms to form AlAl8Cr4 cuboctahedra that share corners with four equivalent AlAl8Cr4 cuboctahedra, corners with eight equivalent CrAl12 cuboctahedra, edges with twenty-four AlAl8Cr4 cuboctahedra, faces with six equivalent CrAl12 cuboctahedra, and faces with twelve AlAl8Cr4 cuboctahedra.