Materials Data on PrNb3O9 by Materials Project
PrNb3O9 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Pr3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Pr–O bond distances ranging from 2.47–2.57 Å. There are three inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded to six O2- atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 32–52°. There are a spread of Nb–O bond distances ranging from 1.82–2.21 Å. In the second Nb5+ site, Nb5+ is bonded to six O2- atoms to form a mixture of distorted edge and corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 27–46°. There are a spread of Nb–O bond distances ranging from 1.86–2.26 Å. In the third Nb5+ site, Nb5+ is bonded to six O2- atoms to form a mixture of distorted edge and corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 27–52°. There are a spread of Nb–O bond distances ranging from 1.86–2.26 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to two Nb5+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to one Pr3+ and two Nb5+ atoms. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Pr3+ and two equivalent Nb5+ atoms. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Pr3+ and two equivalent Nb5+ atoms. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to one Pr3+ and two Nb5+ atoms. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to one Pr3+ and two Nb5+ atoms. In the seventh O2- site, O2- is bonded in a bent 150 degrees geometry to two Nb5+ atoms. In the eighth O2- site, O2- is bonded in a 3-coordinate geometry to one Pr3+ and two Nb5+ atoms. In the ninth O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Nb5+ atoms.