Materials Data on Al5CuSe8 by Materials Project
CuAl5Se8 is Spinel-like structured and crystallizes in the cubic F-43m space group. The structure is three-dimensional. Cu1+ is bonded to four equivalent Se2- atoms to form CuSe4 tetrahedra that share corners with twelve equivalent AlSe6 octahedra. The corner-sharing octahedral tilt angles are 54°. All Cu–Se bond lengths are 2.41 Å. There are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four equivalent Se2- atoms to form corner-sharing AlSe4 tetrahedra. The corner-sharing octahedral tilt angles are 60°. All Al–Se bond lengths are 2.47 Å. In the second Al3+ site, Al3+ is bonded to six Se2- atoms to form AlSe6 octahedra that share corners with three equivalent CuSe4 tetrahedra, corners with three equivalent AlSe4 tetrahedra, and edges with six equivalent AlSe6 octahedra. There are three shorter (2.51 Å) and three longer (2.65 Å) Al–Se bond lengths. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to four Al3+ atoms to form a mixture of distorted corner and edge-sharing SeAl4 tetrahedra. In the second Se2- site, Se2- is bonded in a rectangular see-saw-like geometry to one Cu1+ and three equivalent Al3+ atoms.