Materials Data on Rb2NbCuSe4 by Materials Project
Rb2NbCuSe4 crystallizes in the orthorhombic Fddd space group. The structure is three-dimensional. Rb1+ is bonded to eight equivalent Se2- atoms to form distorted RbSe8 hexagonal bipyramids that share corners with four equivalent RbSe8 hexagonal bipyramids, corners with two equivalent NbSe4 tetrahedra, corners with four equivalent CuSe4 tetrahedra, edges with six equivalent RbSe8 hexagonal bipyramids, edges with two equivalent CuSe4 tetrahedra, edges with three equivalent NbSe4 tetrahedra, and faces with two equivalent RbSe8 hexagonal bipyramids. There are a spread of Rb–Se bond distances ranging from 3.62–3.85 Å. Nb5+ is bonded to four equivalent Se2- atoms to form NbSe4 tetrahedra that share corners with four equivalent RbSe8 hexagonal bipyramids, edges with six equivalent RbSe8 hexagonal bipyramids, and edges with two equivalent CuSe4 tetrahedra. All Nb–Se bond lengths are 2.44 Å. Cu1+ is bonded to four equivalent Se2- atoms to form CuSe4 tetrahedra that share corners with eight equivalent RbSe8 hexagonal bipyramids, edges with four equivalent RbSe8 hexagonal bipyramids, and edges with two equivalent NbSe4 tetrahedra. All Cu–Se bond lengths are 2.47 Å. Se2- is bonded in a 6-coordinate geometry to four equivalent Rb1+, one Nb5+, and one Cu1+ atom.