Materials Data on Hf3Tl2(CuSe4)2 by Materials Project

Abstract

Tl2Cu2Hf3Se8 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are two inequivalent Hf4+ sites. In the first Hf4+ site, 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 43°. There are a spread of Hf–Se bond distances ranging from 2.68–2.72 Å. In the second Hf4+ site, Hf4+ is bonded to six Se2- atoms to form HfSe6 octahedra that share corners with two equivalent HfSe6 octahedra, edges with two equivalent HfSe6 octahedra, and edges with four equivalent CuSe4 tetrahedra. The corner-sharing octahedral tilt angles are 43°. There are two shorter (2.70 Å) and four longer (2.71 Å) Hf–Se bond lengths. Cu1+ is bonded to four Se2- atoms to form CuSe4 tetrahedra that share corners with two equivalent CuSe4 tetrahedra and edges with four HfSe6 octahedra. There are two shorter (2.43 Å) and two longer (2.48 Å) Cu–Se bond lengths. Tl1+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of Tl–Se bond distances ranging from 3.36–3.67 Å. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 3-coordinate geometry to two equivalent Hf4+, one Cu1+, and three equivalent Tl1+ atoms. In the second Se2- site, Se2- is bonded in a 5-coordinate geometry to two equivalent Hf4+, one Cu1+, and two equivalent Tl1+ atoms. In the third Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to three equivalent Hf4+ and one Tl1+ atom. In the fourth Se2- site, Se2- is bonded in a 6-coordinate geometry to two Hf4+, two equivalent Cu1+, and two equivalent Tl1+ atoms.