DOE OSTI2020
Na2TeW2O9 crystallizes in the monoclinic Cc space group. The structure is three-dimensional. there are eight inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Na–O bond distances ranging from 2.49–2.90 Å. In the second Na1+ site, Na1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Na–O bond distances ranging from 2.31–2.89 Å. In the third Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.33–2.72 Å. In the fourth Na1+ site, Na1+ is bonded to seven O2- atoms to form NaO7 pentagonal bipyramids that share corners with four WO6 octahedra, an edgeedge with one NaO7 hexagonal pyramid, and edges with two WO6 octahedra. The corner-sharing octahedra tilt angles range from 35–61°. There are a spread of Na–O bond distances ranging from 2.30–2.63 Å. In the fifth Na1+ site, Na1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Na–O bond distances ranging from 2.34–2.96 Å. In the sixth Na1+ site, Na1+ is bonded to seven O2- atoms to form distorted NaO7 hexagonal pyramids that share a cornercorner with one WO6 octahedra, edges with three WO6 octahedra, and an edgeedge with one NaO7 pentagonal bipyramid. The corner-sharing octahedral tilt angles are 60°. There are a spread of Na–O bond distances ranging from 2.44–2.78 Å. In the seventh Na1+ site, Na1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Na–O bond distances ranging from 2.40–2.96 Å. In the eighth Na1+ site, Na1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Na–O bond distances ranging from 2.38–2.91 Å. There are eight inequivalent W6+ sites. In the first W6+ site, W6+ is bonded to six O2- atoms to form distorted WO6 octahedra that share corners with three WO6 octahedra, a cornercorner with one NaO7 pentagonal bipyramid, an edgeedge with one NaO7 hexagonal pyramid, and an edgeedge with one NaO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 18–42°. There are a spread of W–O bond distances ranging from 1.80–2.19 Å. In the second W6+ site, W6+ is bonded to six O2- atoms to form WO6 octahedra that share corners with three WO6 octahedra, a cornercorner with one NaO7 pentagonal bipyramid, and an edgeedge with one NaO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 18–42°. There are a spread of W–O bond distances ranging from 1.81–2.13 Å. In the third W6+ site, W6+ is bonded to six O2- atoms to form distorted WO6 octahedra that share corners with two WO6 octahedra and a cornercorner with one NaO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 33–44°. There are a spread of W–O bond distances ranging from 1.81–2.21 Å. In the fourth W6+ site, W6+ is bonded to six O2- atoms to form distorted WO6 octahedra that share corners with two WO6 octahedra, a cornercorner with one NaO7 pentagonal bipyramid, and edges with two equivalent NaO7 hexagonal pyramids. The corner-sharing octahedra tilt angles range from 37–38°. There are a spread of W–O bond distances ranging from 1.79–2.22 Å. In the fifth W6+ site, W6+ is bonded to six O2- atoms to form distorted corner-sharing WO6 octahedra. The corner-sharing octahedra tilt angles range from 30–44°. There are a spread of W–O bond distances ranging from 1.77–2.26 Å. In the sixth W6+ site, W6+ is bonded to six O2- atoms to form corner-sharing WO6 octahedra. The corner-sharing octahedra tilt angles range from 18–43°. There are a spread of W–O bond distances ranging from 1.78–2.16 Å. In the seventh W6+ site, W6+ is bonded to six O2- atoms to form distorted WO6 octahedra that share a cornercorner with one NaO7 hexagonal pyramid and corners with three WO6 octahedra. The corner-sharing octahedra tilt angles range from 18–43°. There are a spread of W–O bond distances ranging from 1.81–2.22 Å. In the eighth W6+ site, W6+ is bonded to six O2- atoms to form distorted corner-sharing WO6 octahedra. The corner-sharing octahedra tilt angles range from 21–41°. There are a spread of W–O bond distances ranging from 1.80–2.20 Å. There are four inequivalent Te4+ sites. In the first Te4+ site, Te4+ is bonded in a 3-coordinate geometry to three O2- atoms. There is two shorter (1.90 Å) and one longer (1.91 Å) Te–O bond length. In the second Te4+ site, Te4+ is bonded in a 6-coordinate geometry to four O2- atoms. There are a spread of Te–O bond distances ranging from 1.91–2.62 Å. In the third Te4+ site, Te4+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Te–O bond distances ranging from 1.89–2.70 Å. In the fourth Te4+ site, Te4+ is bonded in a 3-coordinate geometry to three O2- atoms. There is two shorter (1.91 Å) and one longer (1.92 Å) Te–O bond length. There are thirty-six inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one W6+, and one Te4+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to two Na1+ and one W6+ atom. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to two W6+ atoms. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Na1+ and two W6+ atoms. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to two W6+ atoms. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one W6+, and one Te4+ atom. In the seventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Na1+ and one W6+ atom. In the eighth O2- site, O2- is bonded to three Na1+ and one W6+ atom to form a mixture of distorted edge and corner-sharing ONa3W tetrahedra. In the ninth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one W6+, and one Te4+ atom. In the tenth O2- site, O2- is bonded in a 1-coordinate geometry to one Na1+, one W6+, and one Te4+ atom. In the eleventh O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one W6+, and one Te4+ atom. In the twelfth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one W6+, and one Te4+ atom. In the thirteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Na1+ and one W6+ atom. In the fourteenth O2- site, O2- is bonded to three Na1+ and one W6+ atom to form corner-sharing ONa3W tetrahedra. In the fifteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Na1+ and two W6+ atoms. In the sixteenth O2- site, O2- is bonded in a bent 150 degrees geometry to two W6+ atoms. In the seventeenth O2- site, O2- is bonded in a 2-coordinate geometry to two W6+ atoms. In the eighteenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Na1+, one W6+, and one Te4+ atom. In the nineteenth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one W6+, and one Te4+ atom. In the twentieth O2- site, O2- is bonded in a 1-coordinate geometry to two Na1+ and one W6+ atom. In the twenty-first O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one W6+, and one Te4+ atom. In the twenty-second O2- site, O2- is bonded in a 2-coordinate geometry to two Na1+ and two W6+ atoms. In the twenty-third O2- site, O2- is bonded in a 2-coordinate geometry to one Na1+ and one W6+ atom. In the twenty-fourth O2- site, O2- is bonded in a 4-coordinate geometry to three Na1+ and one W6+ atom. In the twenty-fifth O2- site, O2- is bonded in a 4-coordinate geometry to one Na1+, two W6+, and one Te4+ atom. In the twenty-sixth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one W6+, and one Te4+ atom. In the twenty-seventh O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one W6+, and one Te4+ atom. In the twenty-eighth O2- site, O2- is bonded to three Na1+ and one W6+ atom to form a mixture of distorted edge and corner-sharing ONa3W trigonal pyramids. In the twenty-ninth O2- site, O2- is bonded in a 4-coordinate geometry to three Na1+ and one W6+ atom. In the thirtieth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one W6+, and one Te4+ atom. In the thirty-first O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+ and two W6+ atoms. In the thirty-second O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one W6+, and one Te4+ atom. In the thirty-third O2- site, O2- is bonded in a 3-coordinate geometry to two Na1+ and one W6+ atom. In the thirty-fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two W6+ atoms. In the thirty-fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Na1+ and two W6+ atoms. In the thirty-sixth O2- site, O2- is bonded in a 2-coordinate geometry to one Na1+ and two W6+ atoms.