Materials Data on Na2Ti2Se9 by Materials Project
Na2Ti2Se9 crystallizes in the monoclinic P2_1 space group. The structure is three-dimensional. there are eight inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 5-coordinate geometry to five Se+1.11- atoms. There are a spread of Na–Se bond distances ranging from 2.99–3.26 Å. In the second Na1+ site, Na1+ is bonded in a 5-coordinate geometry to five Se+1.11- atoms. There are a spread of Na–Se bond distances ranging from 2.98–3.47 Å. In the third Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six Se+1.11- atoms. There are a spread of Na–Se bond distances ranging from 2.91–3.46 Å. In the fourth Na1+ site, Na1+ is bonded in a 8-coordinate geometry to eight Se+1.11- atoms. There are a spread of Na–Se bond distances ranging from 3.09–3.56 Å. In the fifth Na1+ site, Na1+ is bonded in a 7-coordinate geometry to seven Se+1.11- atoms. There are a spread of Na–Se bond distances ranging from 2.99–3.63 Å. In the sixth Na1+ site, Na1+ is bonded in a 5-coordinate geometry to five Se+1.11- atoms. There are a spread of Na–Se bond distances ranging from 3.06–3.43 Å. In the seventh Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six Se+1.11- atoms. There are a spread of Na–Se bond distances ranging from 3.00–3.40 Å. In the eighth Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six Se+1.11- atoms. There are a spread of Na–Se bond distances ranging from 3.01–3.37 Å. There are eight inequivalent Ti4+ sites. In the first Ti4+ site, Ti4+ is bonded to seven Se+1.11- atoms to form a mixture of distorted edge and face-sharing TiSe7 pentagonal bipyramids. There are a spread of Ti–Se bond distances ranging from 2.51–2.78 Å. In the second Ti4+ site, Ti4+ is bonded to seven Se+1.11- atoms to form a mixture of distorted edge and face-sharing TiSe7 pentagonal bipyramids. There are a spread of Ti–Se bond distances ranging from 2.53–2.74 Å. In the third Ti4+ site, Ti4+ is bonded to seven Se+1.11- atoms to form a mixture of distorted edge and face-sharing TiSe7 pentagonal bipyramids. There are a spread of Ti–Se bond distances ranging from 2.52–2.76 Å. In the fourth Ti4+ site, Ti4+ is bonded to seven Se+1.11- atoms to form a mixture of distorted edge and face-sharing TiSe7 pentagonal bipyramids. There are a spread of Ti–Se bond distances ranging from 2.54–2.72 Å. In the fifth Ti4+ site, Ti4+ is bonded to seven Se+1.11- atoms to form a mixture of distorted edge and face-sharing TiSe7 pentagonal bipyramids. There are a spread of Ti–Se bond distances ranging from 2.51–2.76 Å. In the sixth Ti4+ site, Ti4+ is bonded to seven Se+1.11- atoms to form a mixture of distorted edge and face-sharing TiSe7 pentagonal bipyramids. There are a spread of Ti–Se bond distances ranging from 2.51–2.76 Å. In the seventh Ti4+ site, Ti4+ is bonded to seven Se+1.11- atoms to form a mixture of distorted edge and face-sharing TiSe7 pentagonal bipyramids. There are a spread of Ti–Se bond distances ranging from 2.54–2.71 Å. In the eighth Ti4+ site, Ti4+ is bonded to seven Se+1.11- atoms to form a mixture of distorted edge and face-sharing TiSe7 pentagonal bipyramids. There are a spread of Ti–Se bond distances ranging from 2.52–2.74 Å. There are thirty-six inequivalent Se+1.11- sites. In the first Se+1.11- site, Se+1.11- is bonded in a 3-coordinate geometry to two Na1+ and one Ti4+ atom. In the second Se+1.11- site, Se+1.11- is bonded in a 4-coordinate geometry to two Na1+, one Ti4+, and one Se+1.11- atom. The Se–Se bond length is 2.39 Å. In the third Se+1.11- site, Se+1.11- is bonded in a 4-coordinate geometry to one Na1+, two Ti4+, and one Se+1.11- atom. The Se–Se bond length is 2.41 Å. In the fourth Se+1.11- site, Se+1.11- is bonded in a 3-coordinate geometry to one Na1+ and two Ti4+ atoms. In the fifth Se+1.11- site, Se+1.11- is bonded in a 2-coordinate geometry to two Na1+ and two Ti4+ atoms. In the sixth Se+1.11- site, Se+1.11- is bonded in a 3-coordinate geometry to two Na1+ and one Ti4+ atom. In the seventh Se+1.11- site, Se+1.11- is bonded in a distorted rectangular see-saw-like geometry to two Na1+ and two Ti4+ atoms. In the eighth Se+1.11- site, Se+1.11- is bonded in a 2-coordinate geometry to one Na1+ and one Ti4+ atom. In the ninth Se+1.11- site, Se+1.11- is bonded in a 2-coordinate geometry to two Ti4+ atoms. In the tenth Se+1.11- site, Se+1.11- is bonded in a distorted trigonal bipyramidal geometry to three Na1+ and two Ti4+ atoms. In the eleventh Se+1.11- site, Se+1.11- is bonded in a 3-coordinate geometry to one Na1+ and two Ti4+ atoms. In the twelfth Se+1.11- site, Se+1.11- is bonded in a 2-coordinate geometry to two Ti4+ and one Se+1.11- atom. The Se–Se bond length is 2.39 Å. In the thirteenth Se+1.11- site, Se+1.11- is bonded in a 2-coordinate geometry to one Na1+, two Ti4+, and one Se+1.11- atom. In the fourteenth Se+1.11- site, Se+1.11- is bonded in a 4-coordinate geometry to two Na1+, one Ti4+, and one Se+1.11- atom. The Se–Se bond length is 2.41 Å. In the fifteenth Se+1.11- site, Se+1.11- is bonded in a 4-coordinate geometry to two Na1+ and one Ti4+ atom. In the sixteenth Se+1.11- site, Se+1.11- is bonded in a 2-coordinate geometry to one Na1+, two Ti4+, and one Se+1.11- atom. The Se–Se bond length is 2.39 Å. In the seventeenth Se+1.11- site, Se+1.11- is bonded in a 1-coordinate geometry to one Na1+, one Ti4+, and one Se+1.11- atom. In the eighteenth Se+1.11- site, Se+1.11- is bonded in a 2-coordinate geometry to two Ti4+ atoms. In the nineteenth Se+1.11- site, Se+1.11- is bonded in a 4-coordinate geometry to two Na1+, one Ti4+, and one Se+1.11- atom. The Se–Se bond length is 2.40 Å. In the twentieth Se+1.11- site, Se+1.11- is bonded in a 4-coordinate geometry to two Na1+, one Ti4+, and one Se+1.11- atom. In the twenty-first Se+1.11- site, Se+1.11- is bonded in a distorted bent 120 degrees geometry to one Na1+ and one Ti4+ atom. In the twenty-second Se+1.11- site, Se+1.11- is bonded in a 3-coordinate geometry to two Na1+ and one Ti4+ atom. In the twenty-third Se+1.11- site, Se+1.11- is bonded in a rectangular see-saw-like geometry to two Na1+ and two Ti4+ atoms. In the twenty-fourth Se+1.11- site, Se+1.11- is bonded in a 1-coordinate geometry to two Na1+ and one Ti4+ atom. In the twenty-fifth Se+1.11- site, Se+1.11- is bonded in a 2-coordinate geometry to one Na1+, two Ti4+, and one Se+1.11- atom. In the twenty-sixth Se+1.11- site, Se+1.11- is bonded in a distorted single-bond geometry to one Ti4+ and one Se+1.11- atom. The Se–Se bond length is 2.41 Å. In the twenty-seventh Se+1.11- site, Se+1.11- is bonded in a distorted rectangular see-saw-like geometry to two Na1+ and two Ti4+ atoms. In the twenty-eighth Se+1.11- site, Se+1.11- is bonded in a 4-coordinate geometry to two Na1+, one Ti4+, and one Se+1.11- atom. In the twenty-ninth Se+1.11- site, Se+1.11- is bonded in a 3-coordinate geometry to two Na1+ and one Ti4+ atom. In the thirtieth Se+1.11- site, Se+1.11- is bonded in a 2-coordinate geometry to two Ti4+ and one Se+1.11- atom. In the thirty-first Se+1.11- site, Se+1.11- is bonded in a 2-coordinate geometry to two Ti4+ atoms. In the thirty-second Se+1.11- site, Se+1.11- is bonded in a 2-coordinate geometry to two Ti4+ atoms. In the thirty-third Se+1.11- site, Se+1.11- is bonded in a 4-coordinate geometry to one Na1+, two Ti4+, and one Se+1.11- atom. In the thirty-fourth Se+1.11- site, Se+1.11- is bonded in a 4-coordinate geometry to two Na1+, one Ti4+, and one Se+1.11- atom. The Se–Se bond length is 2.39 Å. In the thirty-fifth Se+1.11- site, Se+1.11- is bonded in a 3-coordinate geometry to two Na1+, two Ti4+, and one Se+1.11- atom. In the thirty-sixth Se+1.11- site, Se+1.11- is bonded in a 3-coordinate geometry to one Na1+ and two Ti4+ atoms.