Materials Data on HfAl3 by Materials Project

Abstract

Al3Hf is Uranium Silicide-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Hf is bonded to twelve Al atoms to form HfAl12 cuboctahedra that share corners with four equivalent HfAl12 cuboctahedra, edges with eight equivalent HfAl12 cuboctahedra, edges with sixteen equivalent AlHf4Al8 cuboctahedra, faces with four equivalent HfAl12 cuboctahedra, and faces with eight equivalent AlHf4Al8 cuboctahedra. There are four shorter (2.79 Å) and eight longer (2.98 Å) Hf–Al bond lengths. There are two inequivalent Al sites. In the first Al site, Al is bonded in a distorted square co-planar geometry to four equivalent Hf and eight equivalent Al atoms. All Al–Al bond lengths are 2.98 Å. In the second Al site, Al is bonded to four equivalent Hf and eight Al atoms to form AlHf4Al8 cuboctahedra that share corners with twelve equivalent AlHf4Al8 cuboctahedra, edges with eight equivalent HfAl12 cuboctahedra, edges with eight equivalent AlHf4Al8 cuboctahedra, faces with four equivalent HfAl12 cuboctahedra, and faces with ten equivalent AlHf4Al8 cuboctahedra. All Al–Al bond lengths are 2.79 Å.