Materials Data on HfAlFe by Materials Project

Abstract

Hf(Fe0.5Al0.5)2 crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. there are two inequivalent Hf sites. In the first Hf site, Hf is bonded in a 12-coordinate geometry to four Hf, seven Fe, and five Al atoms. There are a spread of Hf–Hf bond distances ranging from 3.01–3.10 Å. There are a spread of Hf–Fe bond distances ranging from 2.95–3.00 Å. There are two shorter (2.95 Å) and three longer (3.02 Å) Hf–Al bond lengths. In the second Hf site, Hf is bonded in a 12-coordinate geometry to three equivalent Hf, five Fe, and seven Al atoms. There are a spread of Hf–Fe bond distances ranging from 2.84–3.04 Å. There are a spread of Hf–Al bond distances ranging from 2.87–3.09 Å. There are two inequivalent Fe sites. In the first Fe site, Fe is bonded to six Hf, two equivalent Fe, and four Al atoms to form FeHf6Al4Fe2 cuboctahedra that share corners with four equivalent FeHf6Al2Fe4 cuboctahedra, corners with eight AlHf6Fe6 cuboctahedra, edges with six equivalent FeHf6Al4Fe2 cuboctahedra, faces with eight FeHf6Al4Fe2 cuboctahedra, and faces with twelve AlHf6Fe6 cuboctahedra. Both Fe–Fe bond lengths are 2.50 Å. There are a spread of Fe–Al bond distances ranging from 2.53–2.57 Å. In the second Fe site, Fe is bonded to six Hf, four Fe, and two equivalent Al atoms to form FeHf6Al2Fe4 cuboctahedra that share corners with eight FeHf6Al4Fe2 cuboctahedra, corners with ten AlHf6Al4Fe2 cuboctahedra, edges with two equivalent FeHf6Al2Fe4 cuboctahedra, edges with four equivalent AlHf6Al4Fe2 cuboctahedra, faces with eight AlHf6Fe6 cuboctahedra, and faces with ten FeHf6Al4Fe2 cuboctahedra. There are one shorter (2.54 Å) and one longer (2.55 Å) Fe–Fe bond lengths. There are one shorter (2.54 Å) and one longer (2.56 Å) Fe–Al bond lengths. There are three inequivalent Al sites. In the first Al site, Al is bonded to six Hf and six Fe atoms to form AlHf6Fe6 cuboctahedra that share corners with four equivalent FeHf6Al4Fe2 cuboctahedra, corners with fourteen AlHf6Fe6 cuboctahedra, edges with six AlHf6Fe6 cuboctahedra, faces with four equivalent AlHf6Al4Fe2 cuboctahedra, and faces with fourteen FeHf6Al4Fe2 cuboctahedra. In the second Al site, Al is bonded to six Hf, two equivalent Fe, and four Al atoms to form AlHf6Al4Fe2 cuboctahedra that share corners with eight AlHf6Fe6 cuboctahedra, corners with ten FeHf6Al4Fe2 cuboctahedra, edges with two equivalent AlHf6Al4Fe2 cuboctahedra, edges with four equivalent FeHf6Al2Fe4 cuboctahedra, faces with eight FeHf6Al4Fe2 cuboctahedra, and faces with ten AlHf6Fe6 cuboctahedra. There are a spread of Al–Al bond distances ranging from 2.53–2.57 Å. In the third Al site, Al is bonded to six Hf, two equivalent Fe, and four equivalent Al atoms to form AlHf6Al4Fe2 cuboctahedra that share corners with six AlHf6Fe6 cuboctahedra, corners with twelve FeHf6Al4Fe2 cuboctahedra, edges with six AlHf6Fe6 cuboctahedra, faces with eight equivalent AlHf6Al4Fe2 cuboctahedra, and faces with ten FeHf6Al4Fe2 cuboctahedra.