Materials Data on U12Ir4Se31 by Materials Project

U12Ir4Se31 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are two inequivalent U+4.17+ sites. In the first U+4.17+ site, U+4.17+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of U–Se bond distances ranging from 2.84–3.01 Å. In the second U+4.17+ site, U+4.17+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of U–Se bond distances ranging from 2.87–2.95 Å. Ir3+ is bonded to six Se2- atoms to form IrSe6 octahedra that share corners with two equivalent SeSe12 cuboctahedra. There are four shorter (2.51 Å) and two longer (2.56 Å) Ir–Se bond lengths. There are five inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to three U+4.17+ and one Ir3+ atom. In the second Se2- site, Se2- is bonded in a distorted square co-planar geometry to four equivalent U+4.17+ atoms. In the third Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to four U+4.17+ and one Se2- atom. The Se–Se bond length is 3.63 Å. In the fourth Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to three U+4.17+, one Ir3+, and one Se2- atom. The Se–Se bond length is 3.53 Å. In the fifth Se2- site, Se2- is bonded to twelve Se2- atoms to form SeSe12 cuboctahedra that share corners with eight equivalent IrSe6 octahedra. The corner-sharing octahedral tilt angles are 26°.