Materials Data on HfAl5Ni2 by Materials Project
HfNi2Al5 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, faces with four equivalent HfAl12 cuboctahedra, and faces with four equivalent AlHf4Al8 cuboctahedra. There are four shorter (2.84 Å) and eight longer (2.93 Å) Hf–Al bond lengths. Ni is bonded in a body-centered cubic geometry to eight Al atoms. There are four shorter (2.42 Å) and four longer (2.60 Å) Ni–Al bond lengths. There are four inequivalent Al sites. In the first Al site, Al is bonded in a 12-coordinate geometry to two equivalent Hf, four equivalent Ni, and two equivalent Al atoms. Both Al–Al bond lengths are 2.93 Å. In the second Al site, Al is bonded in a 12-coordinate geometry to two equivalent Hf, four equivalent Ni, and two equivalent Al atoms. Both Al–Al bond lengths are 2.93 Å. In the third Al site, Al is bonded in a 12-coordinate geometry to two equivalent Hf, four equivalent Ni, and two equivalent Al atoms. Both Al–Al bond lengths are 2.93 Å. In the fourth Al site, Al is bonded to four equivalent Hf and eight Al atoms to form distorted AlHf4Al8 cuboctahedra that share corners with four equivalent AlHf4Al8 cuboctahedra, faces with four equivalent HfAl12 cuboctahedra, and faces with four equivalent AlHf4Al8 cuboctahedra.