Materials Data on La2SiO5 by Materials Project

Abstract

La2SiO5 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are two inequivalent La3+ sites. In the first La3+ site, La3+ is bonded to six O2- atoms to form distorted LaO6 octahedra that share corners with four equivalent SiO4 tetrahedra and edges with two equivalent LaO6 octahedra. There are a spread of La–O bond distances ranging from 2.38–2.46 Å. In the second La3+ site, La3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of La–O bond distances ranging from 2.38–2.78 Å. Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four equivalent LaO6 octahedra. The corner-sharing octahedra tilt angles range from 42–68°. There are a spread of Si–O bond distances ranging from 1.64–1.67 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent La3+ and one Si4+ atom. In the second O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to two equivalent La3+ and one Si4+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to three La3+ and one Si4+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to two La3+ and one Si4+ atom. In the fifth O2- site, O2- is bonded to four La3+ atoms to form edge-sharing OLa4 tetrahedra.