Materials Data on La2U2Se9 by Materials Project
U2La2Se9 crystallizes in the orthorhombic Pmma space group. The structure is three-dimensional. U6+ is bonded in a 9-coordinate geometry to nine Se2- atoms. There are a spread of U–Se bond distances ranging from 2.87–3.07 Å. There are two inequivalent La3+ sites. In the first La3+ site, La3+ is bonded in a 10-coordinate geometry to ten Se2- atoms. There are a spread of La–Se bond distances ranging from 3.04–3.37 Å. In the second La3+ site, La3+ is bonded in a 10-coordinate geometry to eight Se2- atoms. There are a spread of La–Se bond distances ranging from 3.11–3.16 Å. There are five inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a distorted see-saw-like geometry to two equivalent U6+ and two equivalent La3+ atoms. In the second Se2- site, Se2- is bonded to two equivalent U6+ and two La3+ atoms to form a mixture of distorted edge and corner-sharing SeLa2U2 trigonal pyramids. In the third Se2- site, Se2- is bonded in a 6-coordinate geometry to two equivalent U6+, two equivalent La3+, and two equivalent Se2- atoms. There are one shorter (2.68 Å) and one longer (2.73 Å) Se–Se bond lengths. In the fourth Se2- site, Se2- is bonded in a 6-coordinate geometry to two equivalent U6+ and two equivalent La3+ atoms. In the fifth Se2- site, Se2- is bonded in a 6-coordinate geometry to two equivalent U6+, two La3+, and two equivalent Se2- atoms. There are one shorter (2.78 Å) and one longer (2.80 Å) Se–Se bond lengths.