Materials Data on UAlFe by Materials Project
UFeAl is Frank-Kasper $\mu$ Phase-derived structured and crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. there are two inequivalent U sites. In the first U site, U is bonded in a 7-coordinate geometry to four U, seven Fe, and five Al atoms. There are a spread of U–U bond distances ranging from 2.80–3.22 Å. There are a spread of U–Fe bond distances ranging from 2.90–3.08 Å. There are a spread of U–Al bond distances ranging from 3.02–3.18 Å. In the second U site, U is bonded in a 5-coordinate geometry to three equivalent U, five Fe, and seven Al atoms. There are a spread of U–Fe bond distances ranging from 2.74–3.02 Å. There are a spread of U–Al bond distances ranging from 2.96–3.24 Å. There are two inequivalent Fe sites. In the first Fe site, Fe is bonded to six U, two equivalent Fe, and four Al atoms to form distorted FeU6Al4Fe2 cuboctahedra that share corners with four equivalent FeU6Al2Fe4 cuboctahedra, corners with eight AlU6Fe6 cuboctahedra, edges with six equivalent FeU6Al4Fe2 cuboctahedra, faces with eight FeU6Al4Fe2 cuboctahedra, and faces with twelve AlU6Fe6 cuboctahedra. Both Fe–Fe bond lengths are 2.67 Å. There are a spread of Fe–Al bond distances ranging from 2.49–2.58 Å. In the second Fe site, Fe is bonded to six U, four Fe, and two equivalent Al atoms to form distorted FeU6Al2Fe4 cuboctahedra that share corners with eight FeU6Al4Fe2 cuboctahedra, corners with ten AlU6Al4Fe2 cuboctahedra, edges with two equivalent FeU6Al2Fe4 cuboctahedra, edges with four equivalent AlU6Al4Fe2 cuboctahedra, faces with eight AlU6Fe6 cuboctahedra, and faces with ten FeU6Al4Fe2 cuboctahedra. There are one shorter (2.58 Å) and one longer (2.64 Å) Fe–Fe bond lengths. There are one shorter (2.49 Å) and one longer (2.58 Å) Fe–Al bond lengths. There are three inequivalent Al sites. In the first Al site, Al is bonded to six U and six Fe atoms to form distorted AlU6Fe6 cuboctahedra that share corners with four equivalent FeU6Al4Fe2 cuboctahedra, corners with fourteen AlU6Fe6 cuboctahedra, edges with six AlU6Fe6 cuboctahedra, faces with four equivalent AlU6Al4Fe2 cuboctahedra, and faces with fourteen FeU6Al4Fe2 cuboctahedra. In the second Al site, Al is bonded to six U, two equivalent Fe, and four Al atoms to form distorted AlU6Al4Fe2 cuboctahedra that share corners with eight AlU6Fe6 cuboctahedra, corners with ten FeU6Al4Fe2 cuboctahedra, edges with two equivalent AlU6Al4Fe2 cuboctahedra, edges with four equivalent FeU6Al2Fe4 cuboctahedra, faces with eight FeU6Al4Fe2 cuboctahedra, and faces with ten AlU6Fe6 cuboctahedra. There are a spread of Al–Al bond distances ranging from 2.53–2.65 Å. In the third Al site, Al is bonded to six U, two equivalent Fe, and four equivalent Al atoms to form distorted AlU6Al4Fe2 cuboctahedra that share corners with six AlU6Fe6 cuboctahedra, corners with twelve FeU6Al4Fe2 cuboctahedra, edges with six AlU6Fe6 cuboctahedra, faces with eight equivalent AlU6Al4Fe2 cuboctahedra, and faces with ten FeU6Al4Fe2 cuboctahedra.