Materials Data on NaCdCuSe2 by Materials Project
NaCuCdSe2 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Na1+ is bonded to five Se2- atoms to form edge-sharing NaSe5 square pyramids. There are a spread of Na–Se bond distances ranging from 3.00–3.08 Å. Cu1+ is bonded in a square co-planar geometry to four Se2- atoms. There are two shorter (2.52 Å) and two longer (2.55 Å) Cu–Se bond lengths. Cd2+ is bonded in a linear geometry to two Se2- atoms. There are one shorter (2.52 Å) and one longer (2.53 Å) Cd–Se bond lengths. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to three equivalent Na1+, two equivalent Cu1+, and one Cd2+ atom to form SeNa3CdCu2 octahedra that share corners with seven equivalent SeNa2CdCu2 square pyramids, edges with four equivalent SeNa3CdCu2 octahedra, and edges with two equivalent SeNa2CdCu2 square pyramids. In the second Se2- site, Se2- is bonded to two equivalent Na1+, two equivalent Cu1+, and one Cd2+ atom to form SeNa2CdCu2 square pyramids that share corners with seven equivalent SeNa3CdCu2 octahedra, edges with two equivalent SeNa3CdCu2 octahedra, and edges with two equivalent SeNa2CdCu2 square pyramids. The corner-sharing octahedra tilt angles range from 1–77°.