Materials Data on Cd(GaSe2)2 by Materials Project
CdGa2Se4 crystallizes in the tetragonal I-4m2 space group. The structure is three-dimensional. Cd2+ is bonded to six Se2- atoms to form CdSe6 octahedra that share corners with two equivalent GaSe6 octahedra, corners with four equivalent CdSe6 octahedra, and edges with eight GaSe6 octahedra. The corner-sharing octahedra tilt angles range from 0–8°. There are four shorter (2.80 Å) and two longer (2.87 Å) Cd–Se bond lengths. There are two inequivalent Ga3+ sites. In the first Ga3+ site, Ga3+ is bonded to six Se2- atoms to form GaSe6 octahedra that share corners with four equivalent GaSe6 octahedra, edges with four equivalent CdSe6 octahedra, and edges with four equivalent GaSe6 octahedra. The corner-sharing octahedral tilt angles are 8°. There are two shorter (2.46 Å) and four longer (2.80 Å) Ga–Se bond lengths. In the second Ga3+ site, Ga3+ is bonded to six Se2- atoms to form GaSe6 octahedra that share corners with two equivalent CdSe6 octahedra, corners with four equivalent GaSe6 octahedra, edges with four equivalent CdSe6 octahedra, and edges with four equivalent GaSe6 octahedra. The corner-sharing octahedra tilt angles range from 0–8°. There are two shorter (2.46 Å) and four longer (2.80 Å) Ga–Se bond lengths. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to two equivalent Cd2+ and three Ga3+ atoms to form a mixture of edge and corner-sharing SeCd2Ga3 square pyramids. In the second Se2- site, Se2- is bonded in a square co-planar geometry to one Cd2+ and three Ga3+ atoms.