Materials Data on BaZn2Si2O7 by Materials Project
BaZn2Si2O7 crystallizes in the orthorhombic Cmc2_1 space group. The structure is three-dimensional. Ba2+ is bonded to five O2- atoms to form distorted BaO5 square pyramids that share corners with four equivalent ZnO4 tetrahedra and corners with six equivalent SiO4 tetrahedra. There are a spread of Ba–O bond distances ranging from 2.67–2.84 Å. Zn2+ is bonded to four O2- atoms to form ZnO4 tetrahedra that share corners with two equivalent BaO5 square pyramids, corners with two equivalent ZnO4 tetrahedra, and corners with four equivalent SiO4 tetrahedra. There is two shorter (1.98 Å) and two longer (2.01 Å) Zn–O bond length. Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three equivalent BaO5 square pyramids, a cornercorner with one SiO4 tetrahedra, and corners with four equivalent ZnO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.62–1.70 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ba2+ and two equivalent Si4+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ba2+, one Zn2+, and one Si4+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ba2+, one Zn2+, and one Si4+ atom. In the fourth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to two equivalent Zn2+ and one Si4+ atom.