Materials Data on UMnC2 by Materials Project
UMnC2 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. U6+ is bonded to seven C4- atoms to form distorted UC7 pentagonal bipyramids that share corners with four equivalent UC7 pentagonal bipyramids, corners with three equivalent MnC5 trigonal bipyramids, edges with four equivalent UC7 pentagonal bipyramids, edges with seven equivalent MnC5 trigonal bipyramids, and faces with two equivalent UC7 pentagonal bipyramids. There are a spread of U–C bond distances ranging from 2.35–2.51 Å. Mn2+ is bonded to five C4- atoms to form MnC5 trigonal bipyramids that share corners with three equivalent UC7 pentagonal bipyramids, corners with four equivalent MnC5 trigonal bipyramids, edges with seven equivalent UC7 pentagonal bipyramids, and edges with two equivalent MnC5 trigonal bipyramids. There are a spread of Mn–C bond distances ranging from 1.98–2.11 Å. There are two inequivalent C4- sites. In the first C4- site, C4- is bonded to four equivalent U6+ and two equivalent Mn2+ atoms to form a mixture of corner, edge, and face-sharing CU4Mn2 octahedra. The corner-sharing octahedra tilt angles range from 13–61°. In the second C4- site, C4- is bonded to three equivalent U6+ and three equivalent Mn2+ atoms to form a mixture of corner, edge, and face-sharing CU3Mn3 octahedra. The corner-sharing octahedra tilt angles range from 13–61°.