Materials Data on K5Na(Ti2Se9)3 by Materials Project

Abstract

K5Na(Ti2Se9)3 crystallizes in the trigonal P31c space group. The structure is three-dimensional. there are three inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 6-coordinate geometry to six Se+1.11- atoms. There are a spread of K–Se bond distances ranging from 3.36–3.64 Å. In the second K1+ site, K1+ is bonded in a 12-coordinate geometry to twelve Se+1.11- atoms. There are a spread of K–Se bond distances ranging from 3.60–3.93 Å. In the third K1+ site, K1+ is bonded in a 9-coordinate geometry to nine Se+1.11- atoms. There are a spread of K–Se bond distances ranging from 3.51–3.64 Å. Na1+ is bonded to six Se+1.11- atoms to form NaSe6 octahedra that share corners with six TiSe7 pentagonal bipyramids. There are three shorter (3.02 Å) and three longer (3.05 Å) Na–Se bond lengths. There are two inequivalent Ti4+ sites. In the first Ti4+ site, Ti4+ is bonded to seven Se+1.11- atoms to form distorted TiSe7 pentagonal bipyramids that share a cornercorner with one NaSe6 octahedra, an edgeedge with one TiSe7 pentagonal bipyramid, and a faceface with one TiSe7 pentagonal bipyramid. The corner-sharing octahedral tilt angles are 52°. There are a spread of Ti–Se bond distances ranging from 2.53–2.76 Å. In the second Ti4+ site, Ti4+ is bonded to seven Se+1.11- atoms to form distorted TiSe7 pentagonal bipyramids that share a cornercorner with one NaSe6 octahedra, an edgeedge with one TiSe7 pentagonal bipyramid, and a faceface with one TiSe7 pentagonal bipyramid. The corner-sharing octahedral tilt angles are 57°. There are a spread of Ti–Se bond distances ranging from 2.52–2.80 Å. There are nine inequivalent Se+1.11- sites. In the first Se+1.11- site, Se+1.11- is bonded in a 2-coordinate geometry to one K1+, one Na1+, one Ti4+, and one Se+1.11- atom. The Se–Se bond length is 2.39 Å. In the second Se+1.11- site, Se+1.11- is bonded in a 2-coordinate geometry to one K1+, two Ti4+, and one Se+1.11- atom. The Se–Se bond length is 2.41 Å. In the third Se+1.11- site, Se+1.11- is bonded in a 2-coordinate geometry to one K1+, two Ti4+, and one Se+1.11- atom. The Se–Se bond length is 2.42 Å. In the fourth Se+1.11- site, Se+1.11- is bonded to four K1+ and two Ti4+ atoms to form distorted face-sharing SeK4Ti2 octahedra. In the fifth Se+1.11- site, Se+1.11- is bonded in a 1-coordinate geometry to one K1+, one Ti4+, and one Se+1.11- atom. In the sixth Se+1.11- site, Se+1.11- is bonded in a 1-coordinate geometry to two K1+ and one Ti4+ atom. In the seventh Se+1.11- site, Se+1.11- is bonded in a 2-coordinate geometry to one K1+ and two Ti4+ atoms. In the eighth Se+1.11- site, Se+1.11- is bonded in a 2-coordinate geometry to one K1+, one Na1+, one Ti4+, and one Se+1.11- atom. In the ninth Se+1.11- site, Se+1.11- is bonded in a 2-coordinate geometry to one K1+, two Ti4+, and one Se+1.11- atom.