Materials Data on U3Fe2Si7 by Materials Project
U3Fe2Si7 crystallizes in the orthorhombic Cmmm space group. The structure is three-dimensional. there are two inequivalent U+4.67+ sites. In the first U+4.67+ site, U+4.67+ is bonded to twelve Si+2.86- atoms to form a mixture of corner and face-sharing USi12 cuboctahedra. There are a spread of U–Si bond distances ranging from 2.84–2.91 Å. In the second U+4.67+ site, U+4.67+ is bonded in a 10-coordinate geometry to ten Si+2.86- atoms. There are a spread of U–Si bond distances ranging from 2.97–3.13 Å. Fe3+ is bonded in a 5-coordinate geometry to five Si+2.86- atoms. There are a spread of Fe–Si bond distances ranging from 2.24–2.28 Å. There are four inequivalent Si+2.86- sites. In the first Si+2.86- site, Si+2.86- is bonded in a 1-coordinate geometry to six equivalent U+4.67+, one Fe3+, and two equivalent Si+2.86- atoms. Both Si–Si bond lengths are 2.42 Å. In the second Si+2.86- site, Si+2.86- is bonded in a 12-coordinate geometry to four U+4.67+, two equivalent Fe3+, and four equivalent Si+2.86- atoms. All Si–Si bond lengths are 2.84 Å. In the third Si+2.86- site, Si+2.86- is bonded in a 12-coordinate geometry to four U+4.67+, two equivalent Fe3+, and six Si+2.86- atoms. Both Si–Si bond lengths are 2.90 Å. In the fourth Si+2.86- site, Si+2.86- is bonded in a square co-planar geometry to four equivalent U+4.67+ and four equivalent Si+2.86- atoms.