Materials Data on Sr2Be2B2O7 by Materials Project
Sr2Be2B2O7 crystallizes in the hexagonal P-6c2 space group. The structure is three-dimensional. there are two inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded to six equivalent O2- atoms to form distorted SrO6 pentagonal pyramids that share corners with six equivalent BeO4 tetrahedra. All Sr–O bond lengths are 2.53 Å. In the second Sr2+ site, Sr2+ is bonded in a distorted q6 geometry to nine O2- atoms. There are three shorter (2.73 Å) and six longer (2.79 Å) Sr–O bond lengths. Be2+ is bonded to four O2- atoms to form BeO4 tetrahedra that share corners with three equivalent SrO6 pentagonal pyramids and a cornercorner with one BeO4 tetrahedra. There is one shorter (1.58 Å) and three longer (1.66 Å) Be–O bond length. B3+ is bonded in a trigonal planar geometry to three equivalent O2- atoms. All B–O bond lengths are 1.38 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to two Sr2+, one Be2+, and one B3+ atom. In the second O2- site, O2- is bonded in a linear geometry to three equivalent Sr2+ and two equivalent Be2+ atoms.