DOE OSTI2020
La2(SiO3)3 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are two inequivalent La3+ sites. In the first La3+ site, La3+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of La–O bond distances ranging from 2.37–2.89 Å. In the second La3+ site, La3+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of La–O bond distances ranging from 2.35–2.74 Å. There are three inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to five O2- atoms to form distorted SiO5 trigonal bipyramids that share corners with two equivalent SiO6 octahedra and an edgeedge with one SiO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 45–54°. There are a spread of Si–O bond distances ranging from 1.70–1.86 Å. In the second Si4+ site, Si4+ is bonded to six O2- atoms to form SiO6 octahedra that share corners with two equivalent SiO4 tetrahedra, corners with two equivalent SiO5 trigonal bipyramids, and edges with two equivalent SiO6 octahedra. There are a spread of Si–O bond distances ranging from 1.77–2.01 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 53–54°. There are a spread of Si–O bond distances ranging from 1.61–1.67 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent La3+ and two equivalent Si4+ atoms. In the second O2- site, O2- is bonded in a 1-coordinate geometry to three 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 distorted L-shaped geometry to two La3+ and two equivalent Si4+ atoms. In the fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Si4+ atoms. In the sixth O2- site, O2- is bonded in a 1-coordinate geometry to two La3+ and one Si4+ atom. In the seventh O2- site, O2- is bonded in a 1-coordinate geometry to two La3+ and one Si4+ atom. In the eighth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two La3+ and two Si4+ atoms. In the ninth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two La3+ and two Si4+ atoms.