Materials Data on PrNb5O14 by Materials Project
PrNb5O14 crystallizes in the orthorhombic Pmmn space group. The structure is three-dimensional. Pr3+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Pr–O bond distances ranging from 2.46–2.89 Å. There are three inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded to seven O2- atoms to form NbO7 pentagonal bipyramids that share corners with two equivalent NbO6 octahedra, corners with two equivalent NbO7 pentagonal bipyramids, and edges with two equivalent NbO6 octahedra. The corner-sharing octahedral tilt angles are 20°. There are a spread of Nb–O bond distances ranging from 1.94–2.19 Å. In the second Nb5+ site, Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with three equivalent NbO6 octahedra, a cornercorner with one NbO7 pentagonal bipyramid, and an edgeedge with one NbO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 16–40°. There are a spread of Nb–O bond distances ranging from 1.91–2.16 Å. In the third 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 1.93–2.50 Å. There are eleven inequivalent O2- sites. In the first O2- site, O2- is bonded in a linear geometry to one Pr3+ and two equivalent Nb5+ atoms. In the second O2- site, O2- is bonded in a linear geometry to two equivalent Nb5+ atoms. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Pr3+ and two equivalent Nb5+ atoms. In the fourth O2- site, O2- is bonded in a linear geometry to two equivalent Nb5+ atoms. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to three Nb5+ atoms. In the sixth O2- site, O2- is bonded in a linear geometry to two equivalent Nb5+ atoms. In the seventh O2- site, O2- is bonded in a distorted trigonal planar geometry to three Nb5+ atoms. In the eighth O2- site, O2- is bonded to two equivalent Pr3+ and two Nb5+ atoms to form a mixture of distorted edge and corner-sharing OPr2Nb2 tetrahedra. In the ninth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Pr3+ and two equivalent Nb5+ atoms. In the tenth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Nb5+ atoms. In the eleventh O2- site, O2- is bonded in a 3-coordinate geometry to one Pr3+ and two equivalent Nb5+ atoms.