Materials Data on Cr4CdAgSe8 by Materials Project

Abstract

Cr4AgCdSe8 is Spinel-derived structured and crystallizes in the cubic F-43m space group. The structure is three-dimensional. Cr+3.25+ is bonded to six Se2- atoms to form CrSe6 octahedra that share corners with three equivalent AgSe4 tetrahedra, corners with three equivalent CdSe4 tetrahedra, and edges with six equivalent CrSe6 octahedra. There are three shorter (2.54 Å) and three longer (2.57 Å) Cr–Se bond lengths. Ag1+ is bonded to four equivalent Se2- atoms to form AgSe4 tetrahedra that share corners with twelve equivalent CrSe6 octahedra. The corner-sharing octahedral tilt angles are 59°. All Ag–Se bond lengths are 2.61 Å. Cd2+ is bonded to four equivalent Se2- atoms to form CdSe4 tetrahedra that share corners with twelve equivalent CrSe6 octahedra. The corner-sharing octahedral tilt angles are 61°. All Cd–Se bond lengths are 2.64 Å. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to three equivalent Cr+3.25+ and one Ag1+ atom to form distorted SeCr3Ag trigonal pyramids that share corners with nine equivalent SeCr3Cd tetrahedra, corners with three equivalent SeCr3Ag trigonal pyramids, and edges with three equivalent SeCr3Ag trigonal pyramids. In the second Se2- site, Se2- is bonded to three equivalent Cr+3.25+ and one Cd2+ atom to form distorted SeCr3Cd tetrahedra that share corners with three equivalent SeCr3Cd tetrahedra, corners with nine equivalent SeCr3Ag trigonal pyramids, and edges with three equivalent SeCr3Cd tetrahedra.