Materials Data on Al3Ge by Materials Project

Al3Ge is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are two inequivalent Al sites. In the first Al site, Al is bonded to eight Al and four equivalent Ge atoms to form distorted AlAl8Ge4 cuboctahedra that share corners with twelve equivalent AlAl8Ge4 cuboctahedra, edges with eight equivalent GeAl12 cuboctahedra, edges with sixteen AlAl8Ge4 cuboctahedra, faces with four equivalent GeAl12 cuboctahedra, and faces with fourteen AlAl8Ge4 cuboctahedra. There are four shorter (2.89 Å) and four longer (2.90 Å) Al–Al bond lengths. All Al–Ge bond lengths are 2.89 Å. In the second Al site, Al is bonded to eight equivalent Al and four equivalent Ge atoms to form AlAl8Ge4 cuboctahedra that share corners with four equivalent AlAl8Ge4 cuboctahedra, corners with eight equivalent GeAl12 cuboctahedra, edges with twenty-four AlAl8Ge4 cuboctahedra, faces with six equivalent GeAl12 cuboctahedra, and faces with twelve AlAl8Ge4 cuboctahedra. All Al–Ge bond lengths are 2.90 Å. Ge is bonded to twelve Al atoms to form GeAl12 cuboctahedra that share corners with four equivalent GeAl12 cuboctahedra, corners with eight equivalent AlAl8Ge4 cuboctahedra, edges with eight equivalent GeAl12 cuboctahedra, edges with sixteen equivalent AlAl8Ge4 cuboctahedra, faces with four equivalent GeAl12 cuboctahedra, and faces with fourteen AlAl8Ge4 cuboctahedra.