Materials Data on NaCuSe by Materials Project
NaCuSe is Matlockite structured and crystallizes in the tetragonal P4/nmm space group. The structure is three-dimensional. Na1+ is bonded to five equivalent Se2- atoms to form distorted NaSe5 trigonal bipyramids that share corners with twelve equivalent CuSe4 tetrahedra, corners with four equivalent NaSe5 trigonal bipyramids, edges with four equivalent CuSe4 tetrahedra, and edges with eight equivalent NaSe5 trigonal bipyramids. There are four shorter (3.00 Å) and one longer (3.02 Å) Na–Se bond lengths. Cu1+ is bonded to four equivalent Se2- atoms to form CuSe4 tetrahedra that share corners with four equivalent CuSe4 tetrahedra, corners with twelve equivalent NaSe5 trigonal bipyramids, edges with four equivalent CuSe4 tetrahedra, and edges with four equivalent NaSe5 trigonal bipyramids. All Cu–Se bond lengths are 2.56 Å. Se2- is bonded in a 9-coordinate geometry to five equivalent Na1+ and four equivalent Cu1+ atoms.