Materials Data on Ca2SiB2O7 by Materials Project
Ca2SiB2O7 crystallizes in the tetragonal P-42_1m 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 2.35–2.60 Å. B3+ is bonded to four O2- atoms to form BO4 tetrahedra that share a cornercorner with one BO4 tetrahedra and corners with two equivalent SiO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.40–1.59 Å. Si4+ is bonded to four equivalent O2- atoms to form SiO4 tetrahedra that share corners with four equivalent BO4 tetrahedra. All Si–O bond lengths are 1.66 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ca2+ and two equivalent B3+ atoms. In the second O2- site, O2- is bonded in a 1-coordinate geometry to three equivalent Ca2+ and one B3+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ca2+, one B3+, and one Si4+ atom.