Materials Data on Ba5(Si2O7)2 by Materials Project

Abstract

Ba5(Si2O7)2 crystallizes in the tetragonal P4/mnc space group. The structure is three-dimensional. there are two inequivalent Ba sites. In the first Ba site, Ba is bonded in a 10-coordinate geometry to ten O atoms. There are a spread of Ba–O bond distances ranging from 2.68–3.14 Å. In the second Ba site, Ba is bonded in a 10-coordinate geometry to ten O atoms. There are two shorter (2.72 Å) and eight longer (3.11 Å) Ba–O bond lengths. Si is bonded to four O atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.62–1.68 Å. There are three inequivalent O sites. In the first O site, O is bonded in a distorted bent 150 degrees geometry to two equivalent Ba and two equivalent Si atoms. In the second O site, O is bonded to five Ba atoms to form corner-sharing OBa5 square pyramids. In the third O site, O is bonded in a distorted single-bond geometry to four Ba and one Si atom.