DOI: 10.17188/1652590
title: Materials Data on UNb6O16 by Materials Project

description: UNb6O16 crystallizes in the triclinic P1 space group. The structure is three-dimensional. U4+ is bonded to six O2- atoms to form UO6 octahedra that share a cornercorner with one NbO6 octahedra, a cornercorner with one NbO4 tetrahedra, and an edgeedge with one NbO6 octahedra. The corner-sharing octahedral tilt angles are 32°. There are a spread of U–O bond distances ranging from 2.14–2.25 Å. There are six inequivalent Nb+4.67+ sites. In the first Nb+4.67+ site, Nb+4.67+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are a spread of Nb–O bond distances ranging from 1.91–2.06 Å. In the second Nb+4.67+ site, Nb+4.67+ is bonded to six O2- atoms to form distorted NbO6 octahedra that share a cornercorner with one NbO6 octahedra, a cornercorner with one NbO4 tetrahedra, a cornercorner with one NbO5 trigonal bipyramid, and an edgeedge with one NbO5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 45°. There are a spread of Nb–O bond distances ranging from 1.85–2.33 Å. In the third Nb+4.67+ site, Nb+4.67+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Nb–O bond distances ranging from 1.75–2.14 Å. In the fourth Nb+4.67+ site, Nb+4.67+ is bonded to four O2- atoms to form distorted NbO4 tetrahedra that share a cornercorner with one UO6 octahedra, corners with two NbO6 octahedra, and a cornercorner with one NbO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 40–52°. There are a spread of Nb–O bond distances ranging from 1.85–2.14 Å. In the fifth Nb+4.67+ site, Nb+4.67+ is bonded to five O2- atoms to form NbO5 trigonal bipyramids that share corners with two NbO6 octahedra, a cornercorner with one NbO4 tetrahedra, and an edgeedge with one NbO6 octahedra. The corner-sharing octahedra tilt angles range from 2–42°. There are a spread of Nb–O bond distances ranging from 1.82–2.18 Å. In the sixth Nb+4.67+ site, Nb+4.67+ is bonded to six O2- atoms to form distorted NbO6 octahedra that share a cornercorner with one UO6 octahedra, a cornercorner with one NbO6 octahedra, a cornercorner with one NbO4 tetrahedra, a cornercorner with one NbO5 trigonal bipyramid, and an edgeedge with one UO6 octahedra. The corner-sharing octahedra tilt angles range from 32–45°. There are a spread of Nb–O bond distances ranging from 1.89–2.16 Å. There are sixteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted T-shaped geometry to one U4+ and two Nb+4.67+ atoms. In the second O2- site, O2- is bonded in a water-like geometry to one U4+ and one Nb+4.67+ atom. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to two Nb+4.67+ atoms. In the fourth O2- site, O2- is bonded in a linear geometry to two Nb+4.67+ atoms. In the fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Nb+4.67+ atoms. In the sixth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three Nb+4.67+ atoms. In the seventh O2- site, O2- is bonded in a single-bond geometry to one Nb+4.67+ atom. In the eighth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one U4+ and one Nb+4.67+ atom. In the ninth O2- site, O2- is bonded in a bent 120 degrees geometry to one U4+ and one Nb+4.67+ atom. In the tenth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Nb+4.67+ atoms. In the eleventh O2- site, O2- is bonded in a distorted trigonal planar geometry to three Nb+4.67+ atoms. In the twelfth O2- site, O2- is bonded in a distorted water-like geometry to two Nb+4.67+ atoms. In the thirteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Nb+4.67+ atoms. In the fourteenth O2- site, O2- is bonded in a water-like geometry to one U4+ and one Nb+4.67+ atom. In the fifteenth O2- site, O2- is bonded in a distorted T-shaped geometry to one U4+ and two Nb+4.67+ atoms. In the sixteenth O2- site, O2- is bonded in a water-like geometry to two Nb+4.67+ atoms.