DOI: 10.17188/1263274
title: Materials Data on Ba4Ti4O9 by Materials Project

description: Ba4Ti4O9 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are six inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a distorted q6 geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.84–2.94 Å. In the second Ba2+ site, Ba2+ is bonded in a distorted q6 geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.83–2.93 Å. In the third Ba2+ site, Ba2+ is bonded in a distorted q6 geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.83–2.93 Å. In the fourth Ba2+ site, Ba2+ is bonded in a distorted q6 geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.83–2.93 Å. In the fifth Ba2+ site, Ba2+ is bonded in a distorted q6 geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.83–2.93 Å. In the sixth Ba2+ site, Ba2+ is bonded in a distorted q6 geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.84–2.94 Å. There are twelve inequivalent Ti+2.50+ sites. In the first Ti+2.50+ site, Ti+2.50+ is bonded to five O2- atoms to form corner-sharing TiO5 square pyramids. There are a spread of Ti–O bond distances ranging from 1.93–2.05 Å. In the second Ti+2.50+ site, Ti+2.50+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are three shorter (1.99 Å) and one longer (2.01 Å) Ti–O bond lengths. In the third Ti+2.50+ site, Ti+2.50+ is bonded to five O2- atoms to form corner-sharing TiO5 square pyramids. There are a spread of Ti–O bond distances ranging from 1.93–2.03 Å. In the fourth Ti+2.50+ site, Ti+2.50+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are a spread of Ti–O bond distances ranging from 1.98–2.01 Å. In the fifth Ti+2.50+ site, Ti+2.50+ is bonded to five O2- atoms to form corner-sharing TiO5 square pyramids. There are a spread of Ti–O bond distances ranging from 1.95–2.05 Å. In the sixth Ti+2.50+ site, Ti+2.50+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are a spread of Ti–O bond distances ranging from 1.98–2.01 Å. In the seventh Ti+2.50+ site, Ti+2.50+ is bonded to five O2- atoms to form corner-sharing TiO5 square pyramids. There are a spread of Ti–O bond distances ranging from 1.91–2.05 Å. In the eighth Ti+2.50+ site, Ti+2.50+ is bonded to five O2- atoms to form corner-sharing TiO5 square pyramids. There are a spread of Ti–O bond distances ranging from 1.92–2.03 Å. In the ninth Ti+2.50+ site, Ti+2.50+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are a spread of Ti–O bond distances ranging from 1.99–2.01 Å. In the tenth Ti+2.50+ site, Ti+2.50+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are a spread of Ti–O bond distances ranging from 1.98–2.02 Å. In the eleventh Ti+2.50+ site, Ti+2.50+ is bonded in a square co-planar geometry to four O2- atoms. There are three shorter (1.99 Å) and one longer (2.02 Å) Ti–O bond lengths. In the twelfth Ti+2.50+ site, Ti+2.50+ is bonded to five O2- atoms to form corner-sharing TiO5 square pyramids. There are a spread of Ti–O bond distances ranging from 1.94–2.05 Å. There are twenty-one inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to four Ba2+ and two Ti+2.50+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to four Ba2+ and two Ti+2.50+ atoms. In the third O2- site, O2- is bonded in a 6-coordinate geometry to four Ba2+ and two Ti+2.50+ atoms. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to four Ba2+ and two Ti+2.50+ atoms. In the fifth O2- site, O2- is bonded in a 6-coordinate geometry to four Ba2+ and two Ti+2.50+ atoms. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to four Ba2+ and two Ti+2.50+ atoms. In the seventh O2- site, O2- is bonded to four Ba2+ and two Ti+2.50+ atoms to form a mixture of distorted edge and corner-sharing OBa4Ti2 octahedra. The corner-sharing octahedra tilt angles range from 1–10°. In the eighth O2- site, O2- is bonded in a 2-coordinate geometry to four Ba2+ and two Ti+2.50+ atoms. In the ninth O2- site, O2- is bonded to four Ba2+ and two Ti+2.50+ atoms to form a mixture of distorted edge and corner-sharing OBa4Ti2 octahedra. The corner-sharing octahedra tilt angles range from 1–10°. In the tenth O2- site, O2- is bonded in a distorted linear geometry to four Ba2+ and two Ti+2.50+ atoms. In the eleventh O2- site, O2- is bonded in a distorted linear geometry to four Ba2+ and two Ti+2.50+ atoms. In the twelfth O2- site, O2- is bonded in a distorted linear geometry to four Ba2+ and two Ti+2.50+ atoms. In the thirteenth O2- site, O2- is bonded in a distorted linear geometry to four Ba2+ and two Ti+2.50+ atoms. In the fourteenth O2- site, O2- is bonded in a 2-coordinate geometry to four Ba2+ and two Ti+2.50+ atoms. In the fifteenth O2- site, O2- is bonded in a 6-coordinate geometry to four Ba2+ and two Ti+2.50+ atoms. In the sixteenth O2- site, O2- is bonded in a 6-coordinate geometry to four Ba2+ and two Ti+2.50+ atoms. In the seventeenth O2- site, O2- is bonded in a 2-coordinate geometry to four Ba2+ and two Ti+2.50+ atoms. In the eighteenth O2- site, O2- is bonded in a 6-coordinate geometry to four Ba2+ and two Ti+2.50+ atoms. In the nineteenth O2- site, O2- is bonded to four Ba2+ and two Ti+2.50+ atoms to form distorted edge-sharing OBa4Ti2 octahedra. In the twentieth O2- site, O2- is bonded in a distorted octahedral geometry to four Ba2+ and two Ti+2.50+ atoms. In the twenty-first O2- site, O2- is bonded in a distorted linear geometry to four Ba2+ and two Ti+2.50+ atoms.