DOE OSTI2020
Ag2Nb4O11 crystallizes in the monoclinic Cc space group. The structure is three-dimensional. there are four inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Nb–O bond distances ranging from 1.97–2.50 Å. In the second Nb5+ site, Nb5+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Nb–O bond distances ranging from 1.97–2.51 Å. In the third Nb5+ site, Nb5+ is bonded to seven O2- atoms to form distorted corner-sharing NbO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 45–47°. There are a spread of Nb–O bond distances ranging from 1.90–2.33 Å. In the fourth Nb5+ site, Nb5+ is bonded to six O2- atoms to form corner-sharing NbO6 octahedra. There are a spread of Nb–O bond distances ranging from 1.91–2.16 Å. There are two inequivalent Ag1+ sites. In the first Ag1+ site, Ag1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ag–O bond distances ranging from 2.57–2.89 Å. In the second Ag1+ site, Ag1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ag–O bond distances ranging from 2.59–2.94 Å. There are eleven inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two Nb5+ and two Ag1+ atoms. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two Nb5+ and two Ag1+ atoms. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to three Nb5+ atoms. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to three Nb5+ atoms. In the fifth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three Nb5+ and one Ag1+ atom. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Nb5+ and one Ag1+ atom. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to three Nb5+ atoms. In the eighth O2- site, O2- is bonded in a 2-coordinate geometry to two Nb5+ and two Ag1+ atoms. In the ninth O2- site, O2- is bonded in a 4-coordinate geometry to two Nb5+ and two Ag1+ atoms. In the tenth O2- site, O2- is bonded in a 4-coordinate geometry to two Nb5+ and two Ag1+ atoms. In the eleventh O2- site, O2- is bonded in a 2-coordinate geometry to two Nb5+ and two Ag1+ atoms.