DOE OSTI2020
K2PbSi3O10 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent K sites. In the first K site, K is bonded in a 8-coordinate geometry to eight O atoms. There are a spread of K–O bond distances ranging from 2.73–3.29 Å. In the second K site, K is bonded in a 8-coordinate geometry to eight O atoms. There are a spread of K–O bond distances ranging from 2.88–3.35 Å. Pb is bonded to six O atoms to form PbO6 octahedra that share corners with six SiO4 tetrahedra. There are a spread of Pb–O bond distances ranging from 2.18–2.21 Å. There are three inequivalent Si sites. In the first Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two equivalent PbO6 octahedra and corners with two SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 53–55°. There are a spread of Si–O bond distances ranging from 1.63–1.65 Å. In the second Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two equivalent PbO6 octahedra and corners with two SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 52–54°. There are a spread of Si–O bond distances ranging from 1.63–1.66 Å. In the third Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two equivalent PbO6 octahedra and corners with two SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 52–57°. There are a spread of Si–O bond distances ranging from 1.62–1.66 Å. There are ten inequivalent O sites. In the first O site, O is bonded in a 1-coordinate geometry to two K, one Pb, and one Si atom. In the second O site, O is bonded in a distorted bent 120 degrees geometry to one K and two Si atoms. In the third O site, O is bonded in a 1-coordinate geometry to one K, one Pb, and one Si atom. In the fourth O site, O is bonded in a 1-coordinate geometry to two K, one Pb, and one Si atom. In the fifth O site, O is bonded in an L-shaped geometry to two equivalent K atoms. In the sixth O site, O is bonded in a 1-coordinate geometry to two K, one Pb, and one Si atom. In the seventh O site, O is bonded in a 2-coordinate geometry to two equivalent K and two Si atoms. In the eighth O site, O is bonded in a 1-coordinate geometry to two K, one Pb, and one Si atom. In the ninth O site, O is bonded in a distorted bent 150 degrees geometry to one K and two Si atoms. In the tenth O site, O is bonded in a distorted trigonal planar geometry to one K, one Pb, and one Si atom.