Materials Data on La2SiO5 by Materials Project

Abstract

La2SiO5 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are three inequivalent La3+ sites. In the first La3+ site, La3+ is bonded to six O2- atoms to form distorted LaO6 octahedra that share corners with two LaO6 octahedra, corners with two SiO4 tetrahedra, edges with four LaO6 octahedra, and an edgeedge with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 45–54°. There are a spread of La–O bond distances ranging from 2.36–2.65 Å. In the second La3+ site, La3+ is bonded to six O2- atoms to form LaO6 octahedra that share corners with two LaO6 octahedra, corners with four SiO4 tetrahedra, and edges with four LaO6 octahedra. The corner-sharing octahedra tilt angles range from 50–54°. There are a spread of La–O bond distances ranging from 2.42–2.47 Å. In the third La3+ site, La3+ is bonded to six O2- atoms to form LaO6 octahedra that share corners with two LaO6 octahedra, corners with four SiO4 tetrahedra, and edges with four LaO6 octahedra. The corner-sharing octahedra tilt angles range from 45–61°. There are a spread of La–O bond distances ranging from 2.40–2.64 Å. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with six LaO6 octahedra and an edgeedge with one LaO6 octahedra. The corner-sharing octahedra tilt angles range from 25–58°. There are a spread of Si–O bond distances ranging from 1.64–1.68 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with eight LaO6 octahedra. The corner-sharing octahedra tilt angles range from 42–56°. There is two shorter (1.66 Å) and two longer (1.67 Å) Si–O bond length. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two La3+ and one Si4+ atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to two La3+ and one Si4+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to two La3+ and one Si4+ atom. In the fourth O2- site, O2- is bonded to four La3+ atoms to form edge-sharing OLa4 tetrahedra. In the fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to two La3+ and one Si4+ atom. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to two La3+ and one Si4+ atom. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent La3+ and one Si4+ atom. In the eighth O2- site, O2- is bonded to four La3+ atoms to form edge-sharing OLa4 tetrahedra.