Materials Data on K2GeSe4 by Materials Project
K2GeSe4 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 4-coordinate geometry to eight Se+1.50- atoms. There are a spread of K–Se bond distances ranging from 3.36–3.90 Å. In the second K1+ site, K1+ is bonded in a 7-coordinate geometry to seven Se+1.50- atoms. There are a spread of K–Se bond distances ranging from 3.41–3.89 Å. Ge4+ is bonded in a tetrahedral geometry to four Se+1.50- atoms. There are a spread of Ge–Se bond distances ranging from 2.30–2.48 Å. There are four inequivalent Se+1.50- sites. In the first Se+1.50- site, Se+1.50- is bonded in a 1-coordinate geometry to three K1+, one Ge4+, and one Se+1.50- atom. The Se–Se bond length is 2.38 Å. In the second Se+1.50- site, Se+1.50- is bonded in a 1-coordinate geometry to three equivalent K1+, one Ge4+, and one Se+1.50- atom. In the third Se+1.50- site, Se+1.50- is bonded in a 6-coordinate geometry to five K1+ and one Ge4+ atom. In the fourth Se+1.50- site, Se+1.50- is bonded to four K1+ and one Ge4+ atom to form a mixture of distorted corner and edge-sharing SeK4Ge trigonal bipyramids.