DOI: 10.17188/1307027
title: Materials Data on Tb4Nb4O11 by Materials Project

description: Tb4Nb4O11 crystallizes in the orthorhombic Pbam space group. The structure is three-dimensional. there are four inequivalent Tb3+ sites. In the first Tb3+ site, Tb3+ is bonded to seven O2- atoms to form distorted TbO7 pentagonal bipyramids that share edges with three TbO7 pentagonal bipyramids and edges with two equivalent NbO5 square pyramids. There are a spread of Tb–O bond distances ranging from 2.27–2.46 Å. In the second Tb3+ site, Tb3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Tb–O bond distances ranging from 2.28–2.67 Å. In the third Tb3+ site, Tb3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Tb–O bond distances ranging from 2.26–2.77 Å. In the fourth Tb3+ site, Tb3+ is bonded to seven O2- atoms to form distorted TbO7 pentagonal bipyramids that share edges with two equivalent TbO7 pentagonal bipyramids and edges with two equivalent NbO5 square pyramids. There are a spread of Tb–O bond distances ranging from 2.33–2.41 Å. There are three inequivalent Nb+2.50+ sites. In the first Nb+2.50+ site, Nb+2.50+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are a spread of Nb–O bond distances ranging from 2.15–2.19 Å. In the second Nb+2.50+ site, Nb+2.50+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are one shorter (2.17 Å) and three longer (2.19 Å) Nb–O bond lengths. In the third Nb+2.50+ site, Nb+2.50+ is bonded to five O2- atoms to form NbO5 square pyramids that share edges with two TbO7 pentagonal bipyramids and edges with two equivalent NbO5 square pyramids. There are a spread of Nb–O bond distances ranging from 2.09–2.13 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded to four Tb3+ atoms to form distorted OTb4 tetrahedra that share corners with eight OTb4 tetrahedra, corners with four equivalent OTb3Nb2 trigonal bipyramids, and edges with four OTb4 tetrahedra. In the second O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Tb3+ and three Nb+2.50+ atoms. In the third O2- site, O2- is bonded to four Tb3+ atoms to form OTb4 tetrahedra that share corners with six OTb4 tetrahedra, corners with four equivalent OTb3Nb2 trigonal bipyramids, edges with four OTb4 tetrahedra, and an edgeedge with one OTb3Nb2 trigonal bipyramid. In the fourth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Tb3+ and three Nb+2.50+ atoms. In the fifth O2- site, O2- is bonded to three Tb3+ and two Nb+2.50+ atoms to form distorted OTb3Nb2 trigonal bipyramids that share corners with eight OTb4 tetrahedra, edges with two OTb4 tetrahedra, an edgeedge with one OTb3Nb2 trigonal bipyramid, and a faceface with one OTb3Nb2 trigonal bipyramid. In the sixth O2- site, O2- is bonded to three Tb3+ and one Nb+2.50+ atom to form distorted OTb3Nb tetrahedra that share corners with seven OTb4 tetrahedra, corners with two equivalent OTb3Nb2 trigonal bipyramids, edges with two OTb4 tetrahedra, and an edgeedge with one OTb3Nb2 trigonal bipyramid. In the seventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Tb3+ and three Nb+2.50+ atoms. In the eighth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Tb3+ and three Nb+2.50+ atoms.