DOI: 10.17188/1651687
title: Materials Data on K2BaNa2Ti4(SiO4)8 by Materials Project

description: K2Na2BaTi4(SiO4)8 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are two inequivalent K sites. In the first K site, K is bonded in a 7-coordinate geometry to seven O atoms. There are a spread of K–O bond distances ranging from 2.85–2.99 Å. In the second K site, K is bonded in a 7-coordinate geometry to seven O atoms. There are a spread of K–O bond distances ranging from 2.86–3.04 Å. Na is bonded to six O atoms to form distorted NaO6 octahedra that share corners with two equivalent TiO6 octahedra, corners with four SiO4 tetrahedra, and an edgeedge with one TiO6 octahedra. The corner-sharing octahedra tilt angles range from 53–64°. There are a spread of Na–O bond distances ranging from 2.33–2.90 Å. Ba is bonded in a 11-coordinate geometry to eleven O atoms. There are a spread of Ba–O bond distances ranging from 2.65–3.13 Å. There are two inequivalent Ti sites. In the first Ti site, Ti is bonded to six O atoms to form TiO6 octahedra that share corners with two equivalent NaO6 octahedra, corners with two equivalent TiO6 octahedra, and corners with four SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 47–64°. There are a spread of Ti–O bond distances ranging from 1.82–2.17 Å. In the second Ti site, Ti is bonded to six O atoms to form TiO6 octahedra that share corners with two equivalent TiO6 octahedra, corners with four SiO4 tetrahedra, and an edgeedge with one NaO6 octahedra. The corner-sharing octahedral tilt angles are 47°. There are a spread of Ti–O bond distances ranging from 1.87–2.05 Å. There are four inequivalent Si sites. In the first Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one NaO6 octahedra, corners with two TiO6 octahedra, and corners with two SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 39–75°. There are a spread of Si–O bond distances ranging from 1.63–1.67 Å. In the second Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one NaO6 octahedra, corners with two TiO6 octahedra, and corners with two SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 50–67°. 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 a cornercorner with one NaO6 octahedra, corners with two TiO6 octahedra, and corners with two SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 45–64°. There is two shorter (1.63 Å) and two longer (1.66 Å) Si–O bond length. In the fourth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one NaO6 octahedra, corners with two TiO6 octahedra, and corners with two SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 40–61°. There are a spread of Si–O bond distances ranging from 1.62–1.67 Å. There are eighteen inequivalent O sites. In the first O site, O is bonded in a 2-coordinate geometry to one Ba, one Ti, and one Si atom. In the second O site, O is bonded in a distorted bent 120 degrees geometry to one Ba, one Ti, and one Si atom. In the third O site, O is bonded in a distorted bent 120 degrees geometry to one Ba and two Ti atoms. In the fourth O site, O is bonded in a 2-coordinate geometry to one Na and two Ti atoms. In the fifth O site, O is bonded in a distorted bent 150 degrees geometry to one Ti and one Si atom. In the sixth O site, O is bonded in a 3-coordinate geometry to one Na, one Ti, and one Si atom. In the seventh O site, O is bonded in a distorted bent 120 degrees geometry to one K, one Ba, one Ti, and one Si atom. In the eighth O site, O is bonded in a distorted bent 150 degrees geometry to one K, one Ti, and one Si atom. In the ninth O site, O is bonded in a distorted bent 150 degrees geometry to two K and two equivalent Si atoms. In the tenth O site, O is bonded in a distorted bent 150 degrees geometry to two K and two equivalent Si atoms. In the eleventh O site, O is bonded in a distorted bent 150 degrees geometry to one Na and two Si atoms. In the twelfth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the thirteenth O site, O is bonded in a distorted bent 150 degrees geometry to one K, one Ba, and two equivalent Si atoms. In the fourteenth O site, O is bonded in a 3-coordinate geometry to one K and two equivalent Si atoms. In the fifteenth O site, O is bonded in a distorted bent 150 degrees geometry to one Ti and one Si atom. In the sixteenth O site, O is bonded in a distorted trigonal planar geometry to one Na, one Ti, and one Si atom. In the seventeenth O site, O is bonded in a 2-coordinate geometry to one Na and one Ba atom. In the eighteenth O site, O is bonded in a distorted trigonal non-coplanar geometry to two K and one Na atom.