Materials Data on K2B2Se7 by Materials Project
K2B2Se7 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. K1+ is bonded in a 9-coordinate geometry to nine Se+1.14- atoms. There are a spread of K–Se bond distances ranging from 3.40–3.86 Å. B3+ is bonded to four Se+1.14- atoms to form corner-sharing BSe4 tetrahedra. There are a spread of B–Se bond distances ranging from 2.05–2.08 Å. There are four inequivalent Se+1.14- sites. In the first Se+1.14- site, Se+1.14- is bonded in a distorted water-like geometry to two equivalent K1+ and two equivalent B3+ atoms. In the second Se+1.14- site, Se+1.14- is bonded in a distorted single-bond geometry to three equivalent K1+ and one B3+ atom. In the third Se+1.14- site, Se+1.14- is bonded in a distorted single-bond geometry to two equivalent K1+ and one B3+ atom. In the fourth Se+1.14- site, Se+1.14- is bonded in a distorted single-bond geometry to three equivalent K1+ and one B3+ atom.