Materials Data on NaHf2CuSe5 by Materials Project

Abstract

NaCuHf2Se5 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. Na1+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of Na–Se bond distances ranging from 3.09–3.55 Å. Hf4+ is bonded to six Se2- atoms to form HfSe6 octahedra that share a cornercorner with one HfSe6 octahedra, edges with four equivalent HfSe6 octahedra, and edges with two equivalent CuSe4 tetrahedra. The corner-sharing octahedral tilt angles are 50°. There are a spread of Hf–Se bond distances ranging from 2.68–2.72 Å. Cu1+ is bonded to four Se2- atoms to form CuSe4 tetrahedra that share corners with two equivalent CuSe4 tetrahedra and edges with four equivalent HfSe6 octahedra. There are two shorter (2.42 Å) and two longer (2.47 Å) Cu–Se bond lengths. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 4-coordinate geometry to one Na1+ and three equivalent Hf4+ atoms. In the second Se2- site, Se2- is bonded to two equivalent Na1+, two equivalent Hf4+, and two equivalent Cu1+ atoms to form distorted edge-sharing SeNa2Hf2Cu2 octahedra. In the third Se2- site, Se2- is bonded in a 5-coordinate geometry to two equivalent Na1+, two equivalent Hf4+, and one Cu1+ atom.