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 AlHf4Al8 cuboctahedra, corners with eight equivalent HfAl12 cuboctahedra, edges with four equivalent HfAl12 cuboctahedra, edges with twenty AlHf4Al8 cuboctahedra, faces with five equivalent HfAl12 cuboctahedra, and faces with thirteen AlHf4Al8 cuboctahedra. There are a spread of Hf–Al bond distances ranging from 2.83–3.00 Å. There are three inequivalent Al sites. In the first Al site, Al is bonded to four equivalent Hf and eight Al atoms to form distorted AlHf4Al8 cuboctahedra that share corners with four equivalent HfAl12 cuboctahedra, corners with eight equivalent AlHf4Al8 cuboctahedra, edges with four equivalent HfAl12 cuboctahedra, edges with twenty AlHf4Al8 cuboctahedra, faces with five equivalent HfAl12 cuboctahedra, and faces with thirteen AlHf4Al8 cuboctahedra. There are four shorter (2.93 Å) and four longer (2.94 Å) Al–Al bond lengths. In the second Al site, Al is bonded to four equivalent Hf and eight Al atoms to form distorted AlHf4Al8 cuboctahedra that share corners with twelve AlHf4Al8 cuboctahedra, edges with eight equivalent HfAl12 cuboctahedra, edges with sixteen AlHf4Al8 cuboctahedra, faces with four equivalent HfAl12 cuboctahedra, and faces with fourteen AlHf4Al8 cuboctahedra. All Al–Al bond lengths are 2.83 Å. In the third Al site, Al is bonded to four equivalent Hf and eight Al atoms to form AlHf4Al8 cuboctahedra that share corners with twelve AlHf4Al8 cuboctahedra, edges with eight equivalent HfAl12 cuboctahedra, edges with sixteen AlHf4Al8 cuboctahedra, faces with four equivalent HfAl12 cuboctahedra, and faces with fourteen AlHf4Al8 cuboctahedra. All Al–Al bond lengths are 2.83 Å.