Materials Data on U2MnFeSe6 by Materials Project
U2MnFeSe6 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. U+3.50+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of U–Se bond distances ranging from 2.90–3.22 Å. Mn2+ is bonded to six Se2- atoms to form MnSe6 octahedra that share corners with two equivalent FeSe6 octahedra and edges with two equivalent MnSe6 octahedra. The corner-sharing octahedral tilt angles are 46°. There are two shorter (2.56 Å) and four longer (2.65 Å) Mn–Se bond lengths. Fe3+ is bonded to six Se2- atoms to form FeSe6 octahedra that share corners with two equivalent MnSe6 octahedra and edges with two equivalent FeSe6 octahedra. The corner-sharing octahedral tilt angles are 46°. There are two shorter (2.52 Å) and four longer (2.58 Å) Fe–Se bond lengths. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 5-coordinate geometry to three equivalent U+3.50+ and two equivalent Mn2+ atoms. In the second Se2- site, Se2- is bonded in a 5-coordinate geometry to three equivalent U+3.50+ and two equivalent Fe3+ atoms. In the third Se2- site, Se2- is bonded to two equivalent U+3.50+, one Mn2+, and one Fe3+ atom to form distorted corner-sharing SeU2MnFe tetrahedra.