Materials Data on K2(FeSe)5 by Materials Project
K2(FeSe)5 crystallizes in the tetragonal I4/m space group. The structure is three-dimensional. K is bonded in a distorted body-centered cubic geometry to eight Se atoms. There are a spread of K–Se bond distances ranging from 3.32–3.53 Å. There are two inequivalent Fe sites. In the first Fe site, Fe is bonded to four Se atoms to form a mixture of distorted corner and edge-sharing FeSe4 tetrahedra. There are a spread of Fe–Se bond distances ranging from 2.47–2.49 Å. In the second Fe site, Fe is bonded to four equivalent Se atoms to form a mixture of distorted corner and edge-sharing FeSe4 tetrahedra. All Fe–Se bond lengths are 2.46 Å. There are two inequivalent Se sites. In the first Se site, Se is bonded in a 7-coordinate geometry to three equivalent K and four Fe atoms. In the second Se site, Se is bonded in a 8-coordinate geometry to four equivalent K and four equivalent Fe atoms.