DOE OSTI2020
Ti12Se16O3 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are nine inequivalent Ti+3.17+ sites. In the first Ti+3.17+ site, Ti+3.17+ is bonded to six Se2- atoms to form a mixture of edge, corner, and face-sharing TiSe6 octahedra. The corner-sharing octahedra tilt angles range from 37–51°. There are a spread of Ti–Se bond distances ranging from 2.55–2.70 Å. In the second Ti+3.17+ site, Ti+3.17+ is bonded in a distorted single-bond geometry to three Se2- and one O2- atom. There are two shorter (2.59 Å) and one longer (2.61 Å) Ti–Se bond lengths. The Ti–O bond length is 1.64 Å. In the third Ti+3.17+ site, Ti+3.17+ is bonded to six Se2- atoms to form a mixture of edge, corner, and face-sharing TiSe6 octahedra. The corner-sharing octahedra tilt angles range from 41–49°. There are a spread of Ti–Se bond distances ranging from 2.56–2.73 Å. In the fourth Ti+3.17+ site, Ti+3.17+ is bonded in a distorted single-bond geometry to four Se2- and one O2- atom. There are a spread of Ti–Se bond distances ranging from 2.51–2.96 Å. The Ti–O bond length is 1.64 Å. In the fifth Ti+3.17+ site, Ti+3.17+ is bonded in a distorted single-bond geometry to four Se2- and one O2- atom. There are a spread of Ti–Se bond distances ranging from 2.59–3.12 Å. The Ti–O bond length is 1.66 Å. In the sixth Ti+3.17+ site, Ti+3.17+ is bonded to six Se2- atoms to form a mixture of edge and corner-sharing TiSe6 octahedra. The corner-sharing octahedra tilt angles range from 37–46°. There are a spread of Ti–Se bond distances ranging from 2.52–2.72 Å. In the seventh Ti+3.17+ site, Ti+3.17+ is bonded to six Se2- atoms to form a mixture of edge, corner, and face-sharing TiSe6 octahedra. The corner-sharing octahedra tilt angles range from 36–46°. There are a spread of Ti–Se bond distances ranging from 2.53–2.75 Å. In the eighth Ti+3.17+ site, Ti+3.17+ is bonded to six Se2- atoms to form a mixture of edge, corner, and face-sharing TiSe6 octahedra. The corner-sharing octahedra tilt angles range from 36–51°. There are a spread of Ti–Se bond distances ranging from 2.56–2.73 Å. In the ninth Ti+3.17+ site, Ti+3.17+ is bonded to six Se2- atoms to form a mixture of edge, corner, and face-sharing TiSe6 octahedra. The corner-sharing octahedra tilt angles range from 39–49°. There are a spread of Ti–Se bond distances ranging from 2.55–2.75 Å. There are twelve inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 6-coordinate geometry to six Ti+3.17+ atoms. In the second Se2- site, Se2- is bonded in a 6-coordinate geometry to six Ti+3.17+ atoms. In the third Se2- site, Se2- is bonded in a 4-coordinate geometry to three Ti+3.17+ atoms. In the fourth Se2- site, Se2- is bonded to four Ti+3.17+ and one O2- atom to form distorted corner-sharing SeTi4O square pyramids. The Se–O bond length is 3.19 Å. In the fifth Se2- site, Se2- is bonded in a 5-coordinate geometry to four Ti+3.17+ and one O2- atom. The Se–O bond length is 2.96 Å. In the sixth Se2- site, Se2- is bonded to four Ti+3.17+ atoms to form distorted corner-sharing SeTi4 trigonal pyramids. In the seventh Se2- site, Se2- is bonded in a 4-coordinate geometry to four Ti+3.17+ atoms. In the eighth Se2- site, Se2- is bonded in a 6-coordinate geometry to four Ti+3.17+ and two O2- atoms. There are one shorter (2.85 Å) and one longer (3.03 Å) Se–O bond lengths. In the ninth Se2- site, Se2- is bonded in a 3-coordinate geometry to three Ti+3.17+ atoms. In the tenth Se2- site, Se2- is bonded in a 4-coordinate geometry to four Ti+3.17+ atoms. In the eleventh Se2- site, Se2- is bonded in a 5-coordinate geometry to four Ti+3.17+ and one O2- atom. The Se–O bond length is 2.74 Å. In the twelfth Se2- site, Se2- is bonded in a 4-coordinate geometry to four Ti+3.17+ atoms. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one Ti+3.17+ and one Se2- atom. In the second O2- site, O2- is bonded in a single-bond geometry to one Ti+3.17+ and four Se2- atoms. In the third O2- site, O2- is bonded in a single-bond geometry to one Ti+3.17+ and one Se2- atom.