Materials Data on Ca(BO2)2 by Materials Project

Abstract

CaB2O4 crystallizes in the orthorhombic Pccn space group. The structure is three-dimensional. Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.31–2.64 Å. There are two inequivalent B3+ sites. In the first B3+ site, B3+ is bonded to four O2- atoms to form corner-sharing BO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.48–1.51 Å. In the second B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There is one shorter (1.37 Å) and two longer (1.38 Å) B–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to four equivalent Ca2+ and one B3+ atom. In the second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two equivalent Ca2+ and two equivalent B3+ atoms. In the third O2- site, O2- is bonded in a 2-coordinate geometry to one Ca2+ and two B3+ atoms. In the fourth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Ca2+ and two B3+ atoms.