Materials Data on Co(SiSe2)2 by Materials Project
Co(SiSe2)2 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Co2+ is bonded to six Se+0.50- atoms to form CoSe6 octahedra that share corners with twelve equivalent SiSe6 octahedra, edges with two equivalent CoSe6 octahedra, and faces with two equivalent SiSe6 octahedra. The corner-sharing octahedra tilt angles range from 44–53°. There are four shorter (2.45 Å) and two longer (2.46 Å) Co–Se bond lengths. Si is bonded to six Se+0.50- atoms to form SiSe6 octahedra that share corners with six equivalent CoSe6 octahedra, edges with six equivalent SiSe6 octahedra, and a faceface with one CoSe6 octahedra. The corner-sharing octahedra tilt angles range from 44–53°. There are a spread of Si–Se bond distances ranging from 2.52–2.72 Å. There are two inequivalent Se+0.50- sites. In the first Se+0.50- site, Se+0.50- is bonded in a rectangular see-saw-like geometry to one Co2+ and three equivalent Si atoms. In the second Se+0.50- site, Se+0.50- is bonded in a 5-coordinate geometry to two equivalent Co2+ and three equivalent Si atoms.