Materials Data on Nb4O9 by Materials Project
Nb4O9 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are four inequivalent Nb+4.50+ sites. In the first Nb+4.50+ site, Nb+4.50+ is bonded to five O2- atoms to form distorted NbO5 square pyramids that share corners with four equivalent NbO6 octahedra and corners with three NbO5 square pyramids. The corner-sharing octahedra tilt angles range from 16–58°. There are a spread of Nb–O bond distances ranging from 1.86–2.26 Å. In the second Nb+4.50+ site, Nb+4.50+ is bonded to five O2- atoms to form NbO5 square pyramids that share corners with five NbO5 square pyramids and an edgeedge with one NbO6 octahedra. There are a spread of Nb–O bond distances ranging from 1.86–2.14 Å. In the third Nb+4.50+ site, Nb+4.50+ is bonded to five O2- atoms to form NbO5 square pyramids that share corners with three equivalent NbO6 octahedra and corners with four NbO5 square pyramids. The corner-sharing octahedra tilt angles range from 38–53°. There are a spread of Nb–O bond distances ranging from 1.93–2.14 Å. In the fourth Nb+4.50+ site, Nb+4.50+ is bonded to six O2- atoms to form a mixture of distorted edge and corner-sharing NbO6 octahedra. There are a spread of Nb–O bond distances ranging from 1.84–2.25 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to three Nb+4.50+ atoms. In the second O2- site, O2- is bonded in a 3-coordinate geometry to three Nb+4.50+ atoms. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to three Nb+4.50+ atoms. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to two Nb+4.50+ atoms. In the fifth O2- site, O2- is bonded in a bent 120 degrees geometry to two Nb+4.50+ atoms. In the sixth O2- site, O2- is bonded in a bent 150 degrees geometry to two Nb+4.50+ atoms. In the seventh O2- site, O2- is bonded in a distorted linear geometry to two Nb+4.50+ atoms. In the eighth O2- site, O2- is bonded in a bent 150 degrees geometry to two Nb+4.50+ atoms. In the ninth O2- site, O2- is bonded in a bent 150 degrees geometry to two Nb+4.50+ atoms.