Materials Data on Sm2U2Se3O4 by Materials Project
U2Sm2Se3O4 crystallizes in the orthorhombic Pbam space group. The structure is three-dimensional. U4+ is bonded in a 3-coordinate geometry to three Se2- and four O2- atoms. There are one shorter (3.02 Å) and two longer (3.11 Å) U–Se bond lengths. There are a spread of U–O bond distances ranging from 2.16–2.43 Å. Sm3+ is bonded in a 3-coordinate geometry to five Se2- and three O2- atoms. There are three shorter (3.06 Å) and two longer (3.10 Å) Sm–Se bond lengths. There are one shorter (2.35 Å) and two longer (2.42 Å) Sm–O bond lengths. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 5-coordinate geometry to one U4+ and four equivalent Sm3+ atoms. In the second Se2- site, Se2- is bonded in a 12-coordinate geometry to four equivalent U4+, two equivalent Sm3+, and six O2- atoms. There are two shorter (3.20 Å) and four longer (3.39 Å) Se–O bond lengths. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent U4+, one Sm3+, and one Se2- atom. In the second O2- site, O2- is bonded to two equivalent U4+, two equivalent Sm3+, and two equivalent Se2- atoms to form a mixture of distorted edge and corner-sharing OSm2U2Se2 tetrahedra.