Materials Data on UAl3Fe7Si2 by Materials Project
UFe7Al3Si2 is beta Uranium-derived structured and crystallizes in the monoclinic Cm space group. The structure is three-dimensional. U is bonded in a 1-coordinate geometry to thirteen Fe, three Al, and four equivalent Si atoms. There are a spread of U–Fe bond distances ranging from 2.71–3.28 Å. There are a spread of U–Al bond distances ranging from 2.97–3.07 Å. There are two shorter (3.10 Å) and two longer (3.22 Å) U–Si bond lengths. There are six inequivalent Fe sites. In the first Fe site, Fe is bonded in a 2-coordinate geometry to one U, six Fe, five Al, and two equivalent Si atoms. There are a spread of Fe–Fe bond distances ranging from 2.46–2.77 Å. There are a spread of Fe–Al bond distances ranging from 2.52–3.03 Å. Both Fe–Si bond lengths are 2.49 Å. In the second Fe site, Fe is bonded to two equivalent U, four Fe, four Al, and two equivalent Si atoms to form distorted FeU2Al4Fe4Si2 cuboctahedra that share corners with four equivalent SiU2Al3Fe5Si2 cuboctahedra, edges with two equivalent FeU2Al4Fe4Si2 cuboctahedra, edges with two equivalent SiU2Al3Fe5Si2 cuboctahedra, and faces with four equivalent SiU2Al3Fe5Si2 cuboctahedra. There are a spread of Fe–Fe bond distances ranging from 2.49–2.71 Å. There are a spread of Fe–Al bond distances ranging from 2.59–2.63 Å. Both Fe–Si bond lengths are 2.39 Å. In the third Fe site, Fe is bonded in a 12-coordinate geometry to two equivalent U, six Fe, two Al, and two equivalent Si atoms. There are a spread of Fe–Fe bond distances ranging from 2.42–2.61 Å. There are one shorter (2.58 Å) and one longer (2.67 Å) Fe–Al bond lengths. Both Fe–Si bond lengths are 2.40 Å. In the fourth Fe site, Fe is bonded in a 12-coordinate geometry to two equivalent U, five Fe, three Al, and two equivalent Si atoms. Both Fe–Fe bond lengths are 2.44 Å. There are one shorter (2.57 Å) and two longer (2.61 Å) Fe–Al bond lengths. Both Fe–Si bond lengths are 2.36 Å. In the fifth Fe site, Fe is bonded in a 12-coordinate geometry to two equivalent U, five Fe, three Al, and two equivalent Si atoms. Both Fe–Fe bond lengths are 2.44 Å. There are two shorter (2.61 Å) and one longer (2.64 Å) Fe–Al bond lengths. Both Fe–Si bond lengths are 2.36 Å. In the sixth Fe site, Fe is bonded in a 12-coordinate geometry to two equivalent U, seven Fe, and three Al atoms. There are one shorter (2.29 Å) and one longer (2.43 Å) Fe–Fe bond lengths. There are a spread of Fe–Al bond distances ranging from 2.46–2.55 Å. There are three inequivalent Al sites. In the first Al site, Al is bonded in a 9-coordinate geometry to one U, seven Fe, four Al, and two equivalent Si atoms. There are two shorter (2.85 Å) and two longer (2.96 Å) Al–Al bond lengths. Both Al–Si bond lengths are 2.70 Å. In the second Al site, Al is bonded in a 10-coordinate geometry to one U, eight Fe, three Al, and two equivalent Si atoms. The Al–Al bond length is 2.49 Å. Both Al–Si bond lengths are 2.64 Å. In the third Al site, Al is bonded in a 10-coordinate geometry to one U, eight Fe, three Al, and two equivalent Si atoms. Both Al–Si bond lengths are 2.59 Å. Si is bonded to two equivalent U, five Fe, three Al, and two equivalent Si atoms to form distorted SiU2Al3Fe5Si2 cuboctahedra that share corners with two equivalent FeU2Al4Fe4Si2 cuboctahedra, corners with six equivalent SiU2Al3Fe5Si2 cuboctahedra, an edgeedge with one FeU2Al4Fe4Si2 cuboctahedra, faces with two equivalent FeU2Al4Fe4Si2 cuboctahedra, and faces with two equivalent SiU2Al3Fe5Si2 cuboctahedra. There are one shorter (2.34 Å) and one longer (2.38 Å) Si–Si bond lengths.