Materials Data on Cr3B7O13F by Materials Project
(Cr3B7O13)2F2 crystallizes in the cubic F-43c space group. The structure is three-dimensional and consists of eight hydrofluoric acid molecules and one Cr3B7O13 framework. In the Cr3B7O13 framework, Cr2+ is bonded in a square co-planar geometry to four equivalent O2- atoms. All Cr–O bond lengths are 2.08 Å. There are two inequivalent B3+ sites. In the first B3+ site, B3+ is bonded to four equivalent O2- atoms to form corner-sharing BO4 tetrahedra. All B–O bond lengths are 1.47 Å. In the second B3+ site, B3+ is bonded to four O2- atoms to form corner-sharing BO4 tetrahedra. There is three shorter (1.44 Å) and one longer (1.69 Å) B–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a tetrahedral geometry to four equivalent B3+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to one Cr2+ and two B3+ atoms.