Materials Data on TmCuS2 by Materials Project
TmCuS2 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Tm3+ is bonded to six S2- atoms to form TmS6 octahedra that share corners with four equivalent TmS6 octahedra, corners with six equivalent CuS4 tetrahedra, edges with four equivalent TmS6 octahedra, and edges with three equivalent CuS4 tetrahedra. The corner-sharing octahedral tilt angles are 51°. There are a spread of Tm–S bond distances ranging from 2.63–2.77 Å. Cu1+ is bonded to four S2- atoms to form CuS4 tetrahedra that share corners with six equivalent TmS6 octahedra, corners with two equivalent CuS4 tetrahedra, edges with three equivalent TmS6 octahedra, and edges with two equivalent CuS4 tetrahedra. The corner-sharing octahedra tilt angles range from 13–60°. There are a spread of Cu–S bond distances ranging from 2.30–2.41 Å. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to three equivalent Tm3+ and one Cu1+ atom. In the second S2- site, S2- is bonded to three equivalent Tm3+ and three equivalent Cu1+ atoms to form distorted edge-sharing STm3Cu3 octahedra.