DOI: 10.17188/1192593
title: Materials Data on K2Ti(Si2O5)3 by Materials Project

description: K2TiSi6O15 crystallizes in the monoclinic Cc space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded to eight O2- atoms to form distorted KO8 hexagonal bipyramids that share a cornercorner with one TiO6 octahedra, corners with six SiO4 tetrahedra, edges with three SiO4 tetrahedra, and a faceface with one TiO6 octahedra. The corner-sharing octahedral tilt angles are 54°. There are a spread of K–O bond distances ranging from 2.77–3.31 Å. In the second K1+ site, K1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of K–O bond distances ranging from 2.78–3.32 Å. Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share a cornercorner with one KO8 hexagonal bipyramid, corners with six SiO4 tetrahedra, and a faceface with one KO8 hexagonal bipyramid. There are a spread of Ti–O bond distances ranging from 1.94–2.00 Å. There are six inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two equivalent KO8 hexagonal bipyramids, a cornercorner with one TiO6 octahedra, and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 28°. There are a spread of Si–O bond distances ranging from 1.60–1.66 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one KO8 hexagonal bipyramid, a cornercorner with one TiO6 octahedra, and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 48°. There are a spread of Si–O bond distances ranging from 1.61–1.66 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one KO8 hexagonal bipyramid, a cornercorner with one TiO6 octahedra, corners with three SiO4 tetrahedra, and an edgeedge with one KO8 hexagonal bipyramid. The corner-sharing octahedral tilt angles are 45°. There are a spread of Si–O bond distances ranging from 1.61–1.66 Å. In the fourth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one KO8 hexagonal bipyramid, a cornercorner with one TiO6 octahedra, and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 39°. There are a spread of Si–O bond distances ranging from 1.60–1.66 Å. In the fifth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one KO8 hexagonal bipyramid, a cornercorner with one TiO6 octahedra, corners with three SiO4 tetrahedra, and an edgeedge with one KO8 hexagonal bipyramid. The corner-sharing octahedral tilt angles are 46°. There are a spread of Si–O bond distances ranging from 1.61–1.66 Å. In the sixth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one TiO6 octahedra, corners with three SiO4 tetrahedra, and an edgeedge with one KO8 hexagonal bipyramid. The corner-sharing octahedral tilt angles are 48°. There are a spread of Si–O bond distances ranging from 1.60–1.67 Å. There are fifteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two K1+, one Ti4+, and one Si4+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to two K1+, one Ti4+, and one Si4+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one Ti4+, and one Si4+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one K1+, one Ti4+, and one Si4+ atom. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to one K1+ and two Si4+ atoms. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one Ti4+, and one Si4+ atom. In the seventh O2- site, O2- is bonded in a bent 120 degrees geometry to two K1+ and two Si4+ atoms. In the eighth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one K1+ and two Si4+ atoms. In the ninth O2- site, O2- is bonded in a linear geometry to two Si4+ atoms. In the tenth O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one Ti4+, and one Si4+ atom. In the eleventh O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one K1+ and two Si4+ atoms. In the twelfth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the thirteenth O2- site, O2- is bonded in a bent 150 degrees geometry to one K1+ and two Si4+ atoms. In the fourteenth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one K1+ and two Si4+ atoms. In the fifteenth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms.