Materials Data on UNbN2 by Materials Project
UNbN2 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. U4+ is bonded to seven N3- atoms to form distorted UN7 pentagonal bipyramids that share corners with four equivalent UN7 pentagonal bipyramids, corners with three equivalent NbN5 trigonal bipyramids, edges with four equivalent UN7 pentagonal bipyramids, edges with seven equivalent NbN5 trigonal bipyramids, and faces with two equivalent UN7 pentagonal bipyramids. There are a spread of U–N bond distances ranging from 2.35–2.52 Å. Nb2+ is bonded to five N3- atoms to form NbN5 trigonal bipyramids that share corners with three equivalent UN7 pentagonal bipyramids, corners with four equivalent NbN5 trigonal bipyramids, edges with seven equivalent UN7 pentagonal bipyramids, and edges with two equivalent NbN5 trigonal bipyramids. There are a spread of Nb–N bond distances ranging from 2.18–2.26 Å. There are two inequivalent N3- sites. In the first N3- site, N3- is bonded to four equivalent U4+ and two equivalent Nb2+ atoms to form a mixture of edge, face, and corner-sharing NU4Nb2 octahedra. The corner-sharing octahedra tilt angles range from 17–57°. In the second N3- site, N3- is bonded to three equivalent U4+ and three equivalent Nb2+ atoms to form a mixture of edge, face, and corner-sharing NU3Nb3 octahedra. The corner-sharing octahedra tilt angles range from 17–57°.