Materials Data on K2Ge2Se5 by Materials Project

K2Ge2Se5 crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. there are three inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 5-coordinate geometry to five Se2- atoms. There are a spread of K–Se bond distances ranging from 3.24–3.74 Å. In the second K1+ site, K1+ is bonded in a 6-coordinate geometry to six Se2- atoms. There are a spread of K–Se bond distances ranging from 3.46–3.90 Å. In the third K1+ site, K1+ is bonded in a 7-coordinate geometry to seven Se2- atoms. There are a spread of K–Se bond distances ranging from 3.33–3.92 Å. There are three inequivalent Ge4+ sites. In the first Ge4+ site, Ge4+ is bonded to four Se2- atoms to form corner-sharing GeSe4 tetrahedra. There are a spread of Ge–Se bond distances ranging from 2.32–2.43 Å. In the second Ge4+ site, Ge4+ is bonded to four Se2- atoms to form corner-sharing GeSe4 tetrahedra. There are a spread of Ge–Se bond distances ranging from 2.30–2.43 Å. In the third Ge4+ site, Ge4+ is bonded to four Se2- atoms to form corner-sharing GeSe4 tetrahedra. There are a spread of Ge–Se bond distances ranging from 2.31–2.41 Å. There are seven inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to two K1+ and two Ge4+ atoms. In the second Se2- site, Se2- is bonded in a water-like geometry to two equivalent Ge4+ atoms. In the third Se2- site, Se2- is bonded to four K1+ and one Ge4+ atom to form distorted SeK4Ge trigonal bipyramids that share corners with three equivalent SeK3Ge tetrahedra and edges with two equivalent SeK4Ge trigonal bipyramids. In the fourth Se2- site, Se2- is bonded in a distorted water-like geometry to one K1+ and two Ge4+ atoms. In the fifth Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to two K1+ and two Ge4+ atoms. In the sixth Se2- site, Se2- is bonded to three K1+ and one Ge4+ atom to form distorted corner-sharing SeK3Ge tetrahedra. In the seventh Se2- site, Se2- is bonded in a 5-coordinate geometry to four K1+ and one Ge4+ atom.