Materials Data on KBe2B3O7 by Materials Project

Abstract

KBe2B3O7 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. K1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of K–O bond distances ranging from 2.81–2.90 Å. Be2+ is bonded to four O2- atoms to form a mixture of edge and corner-sharing BeO4 tetrahedra. There are a spread of Be–O bond distances ranging from 1.58–1.70 Å. There are two inequivalent B3+ sites. In the first B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There is one shorter (1.38 Å) and two longer (1.39 Å) B–O bond length. In the second B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of B–O bond distances ranging from 1.34–1.42 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent K1+, one Be2+, and one B3+ atom. In the second O2- site, O2- is bonded in a trigonal planar geometry to two equivalent Be2+ and one B3+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one K1+, two equivalent Be2+, and one B3+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one K1+ and two B3+ atoms.