Materials Data on Ba2MgSi2O7 by Materials Project
Ba2MgSi2O7 crystallizes in the tetragonal P-42_1m space group. The structure is three-dimensional. Ba2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ba–O bond distances ranging from 2.70–2.96 Å. Mg2+ is bonded to four equivalent O2- atoms to form MgO4 tetrahedra that share corners with four equivalent SiO4 tetrahedra. All Mg–O bond lengths are 1.99 Å. Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one SiO4 tetrahedra and corners with two equivalent MgO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.62–1.69 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ba2+, one Mg2+, and one Si4+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to three equivalent Ba2+ and one Si4+ atom. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent Ba2+ and two equivalent Si4+ atoms.