Materials Data on K2Ag2GeSe4 by Materials Project
K2Ag2GeSe4 crystallizes in the orthorhombic Fddd space group. The structure is three-dimensional. K1+ is bonded to six equivalent Se2- atoms to form distorted KSe6 octahedra that share corners with four equivalent KSe6 octahedra, edges with four equivalent KSe6 octahedra, and edges with three equivalent GeSe4 tetrahedra. The corner-sharing octahedral tilt angles are 19°. There are a spread of K–Se bond distances ranging from 3.40–3.63 Å. Ag1+ is bonded in a 2-coordinate geometry to four equivalent Se2- atoms. There are two shorter (2.54 Å) and two longer (3.27 Å) Ag–Se bond lengths. Ge4+ is bonded to four equivalent Se2- atoms to form GeSe4 tetrahedra that share edges with six equivalent KSe6 octahedra. All Ge–Se bond lengths are 2.42 Å. Se2- is bonded in a 6-coordinate geometry to three equivalent K1+, two equivalent Ag1+, and one Ge4+ atom.