DOE OSTI2020
W3O8 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are six inequivalent W+5.33+ sites. In the first W+5.33+ site, W+5.33+ is bonded to seven O2- atoms to form WO7 pentagonal bipyramids that share corners with two WO6 octahedra, corners with three WO7 pentagonal bipyramids, an edgeedge with one WO6 octahedra, and edges with two WO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 45–46°. There are a spread of W–O bond distances ranging from 1.88–2.18 Å. In the second W+5.33+ site, W+5.33+ is bonded to seven O2- atoms to form WO7 pentagonal bipyramids that share corners with two WO6 octahedra, corners with three WO7 pentagonal bipyramids, an edgeedge with one WO6 octahedra, and edges with two WO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 43–44°. There are a spread of W–O bond distances ranging from 1.88–2.17 Å. In the third W+5.33+ site, W+5.33+ is bonded to seven O2- atoms to form WO7 pentagonal bipyramids that share corners with two WO6 octahedra, corners with three WO7 pentagonal bipyramids, an edgeedge with one WO6 octahedra, and edges with two WO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 42°. There are a spread of W–O bond distances ranging from 1.99–2.14 Å. In the fourth W+5.33+ site, W+5.33+ is bonded to seven O2- atoms to form WO7 pentagonal bipyramids that share corners with two WO6 octahedra, corners with three WO7 pentagonal bipyramids, an edgeedge with one WO6 octahedra, and edges with two WO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 43°. There are a spread of W–O bond distances ranging from 1.88–2.13 Å. In the fifth W+5.33+ site, W+5.33+ is bonded to six O2- atoms to form WO6 octahedra that share corners with two equivalent WO6 octahedra, corners with four WO7 pentagonal bipyramids, and edges with two WO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 1°. There are a spread of W–O bond distances ranging from 1.93–2.03 Å. In the sixth W+5.33+ site, W+5.33+ is bonded to six O2- atoms to form WO6 octahedra that share corners with two equivalent WO6 octahedra, corners with four WO7 pentagonal bipyramids, and edges with two WO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 1°. There are a spread of W–O bond distances ranging from 1.94–2.04 Å. There are thirteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to three W+5.33+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to three W+5.33+ atoms. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to three W+5.33+ atoms. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to three W+5.33+ atoms. In the fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to three W+5.33+ atoms. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to three W+5.33+ atoms. In the seventh O2- site, O2- is bonded in a distorted trigonal planar geometry to three W+5.33+ atoms. In the eighth O2- site, O2- is bonded in a distorted trigonal planar geometry to three W+5.33+ atoms. In the ninth O2- site, O2- is bonded in a linear geometry to two W+5.33+ atoms. In the tenth O2- site, O2- is bonded in a linear geometry to two W+5.33+ atoms. In the eleventh O2- site, O2- is bonded in a linear geometry to two W+5.33+ atoms. In the twelfth O2- site, O2- is bonded in a linear geometry to two W+5.33+ atoms. In the thirteenth O2- site, O2- is bonded in a linear geometry to two W+5.33+ atoms.