DOE OSTI2020
Zr6Nb2O17 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are twelve inequivalent Zr4+ sites. In the first Zr4+ site, Zr4+ is bonded in a 6-coordinate geometry to eight O2- atoms. There are a spread of Zr–O bond distances ranging from 2.04–2.71 Å. In the second Zr4+ site, Zr4+ is bonded in a 6-coordinate geometry to eight O2- atoms. There are a spread of Zr–O bond distances ranging from 2.11–2.68 Å. In the third Zr4+ site, Zr4+ is bonded to seven O2- atoms to form distorted ZrO7 pentagonal bipyramids that share corners with two ZrO7 pentagonal bipyramids, corners with two equivalent NbO7 pentagonal bipyramids, edges with two ZrO7 pentagonal bipyramids, and edges with two equivalent NbO7 pentagonal bipyramids. There are a spread of Zr–O bond distances ranging from 2.06–2.27 Å. In the fourth Zr4+ site, Zr4+ is bonded to seven O2- atoms to form distorted ZrO7 pentagonal bipyramids that share a cornercorner with one NbO7 pentagonal bipyramid, corners with three ZrO7 pentagonal bipyramids, an edgeedge with one NbO7 pentagonal bipyramid, and edges with three ZrO7 pentagonal bipyramids. There are a spread of Zr–O bond distances ranging from 2.05–2.28 Å. In the fifth Zr4+ site, Zr4+ is bonded to seven O2- atoms to form distorted ZrO7 pentagonal bipyramids that share a cornercorner with one NbO7 pentagonal bipyramid, corners with three ZrO7 pentagonal bipyramids, an edgeedge with one NbO7 pentagonal bipyramid, and edges with three ZrO7 pentagonal bipyramids. There are a spread of Zr–O bond distances ranging from 2.07–2.28 Å. In the sixth Zr4+ site, Zr4+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Zr–O bond distances ranging from 2.08–2.36 Å. In the seventh Zr4+ site, Zr4+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Zr–O bond distances ranging from 2.04–2.50 Å. In the eighth Zr4+ site, Zr4+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Zr–O bond distances ranging from 2.04–2.48 Å. In the ninth Zr4+ site, Zr4+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Zr–O bond distances ranging from 2.09–2.36 Å. In the tenth Zr4+ site, Zr4+ is bonded to seven O2- atoms to form distorted ZrO7 pentagonal bipyramids that share corners with two NbO7 pentagonal bipyramids, corners with three ZrO7 pentagonal bipyramids, edges with two NbO7 pentagonal bipyramids, and edges with three ZrO7 pentagonal bipyramids. There are a spread of Zr–O bond distances ranging from 2.06–2.29 Å. In the eleventh Zr4+ site, Zr4+ is bonded to seven O2- atoms to form distorted ZrO7 pentagonal bipyramids that share corners with two NbO7 pentagonal bipyramids, corners with three ZrO7 pentagonal bipyramids, edges with two NbO7 pentagonal bipyramids, and edges with three ZrO7 pentagonal bipyramids. There are a spread of Zr–O bond distances ranging from 2.05–2.27 Å. In the twelfth Zr4+ site, Zr4+ is bonded to seven O2- atoms to form distorted ZrO7 pentagonal bipyramids that share corners with two ZrO7 pentagonal bipyramids, corners with two equivalent NbO7 pentagonal bipyramids, edges with two ZrO7 pentagonal bipyramids, and edges with two equivalent NbO7 pentagonal bipyramids. There are a spread of Zr–O bond distances ranging from 2.06–2.28 Å. There are four inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded to seven O2- atoms to form distorted NbO7 pentagonal bipyramids that share corners with four ZrO7 pentagonal bipyramids and edges with four ZrO7 pentagonal bipyramids. There are a spread of Nb–O bond distances ranging from 1.98–2.22 Å. In the second 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 1.91–2.22 Å. In the third Nb5+ site, Nb5+ is bonded to seven O2- atoms to form distorted NbO7 pentagonal bipyramids that share corners with two ZrO7 pentagonal bipyramids and edges with two ZrO7 pentagonal bipyramids. There are a spread of Nb–O bond distances ranging from 1.91–2.22 Å. In the fourth Nb5+ site, Nb5+ is bonded to seven O2- atoms to form distorted NbO7 pentagonal bipyramids that share corners with four ZrO7 pentagonal bipyramids and edges with four ZrO7 pentagonal bipyramids. There are a spread of Nb–O bond distances ranging from 1.98–2.22 Å. There are thirty-four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two Zr4+ and one Nb5+ atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to three Zr4+ atoms. In the third O2- site, O2- is bonded in a 3-coordinate geometry to three Zr4+ and one Nb5+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to three Zr4+ and one Nb5+ atom. In the fifth O2- site, O2- is bonded in a trigonal planar geometry to two Zr4+ and one Nb5+ atom. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Zr4+ and one Nb5+ atom. In the seventh O2- site, O2- is bonded to three Zr4+ and one Nb5+ atom to form a mixture of edge and corner-sharing OZr3Nb tetrahedra. In the eighth O2- site, O2- is bonded to three Zr4+ and one Nb5+ atom to form a mixture of edge and corner-sharing OZr3Nb tetrahedra. In the ninth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Zr4+ and one Nb5+ atom. In the tenth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Zr4+ atoms. In the eleventh O2- site, O2- is bonded to three Zr4+ and one Nb5+ atom to form a mixture of distorted edge and corner-sharing OZr3Nb tetrahedra. In the twelfth O2- site, O2- is bonded to three Zr4+ and one Nb5+ atom to form a mixture of edge and corner-sharing OZr3Nb tetrahedra. In the thirteenth O2- site, O2- is bonded in a 3-coordinate geometry to two Zr4+ and one Nb5+ atom. In the fourteenth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to two Zr4+ and one Nb5+ atom. In the fifteenth O2- site, O2- is bonded to three Zr4+ and one Nb5+ atom to form a mixture of edge and corner-sharing OZr3Nb tetrahedra. In the sixteenth O2- site, O2- is bonded to three Zr4+ and one Nb5+ atom to form a mixture of distorted edge and corner-sharing OZr3Nb tetrahedra. In the seventeenth O2- site, O2- is bonded in a 3-coordinate geometry to three Zr4+ atoms. In the eighteenth O2- site, O2- is bonded in a 3-coordinate geometry to three Zr4+ atoms. In the nineteenth O2- site, O2- is bonded to three Zr4+ and one Nb5+ atom to form a mixture of edge and corner-sharing OZr3Nb tetrahedra. In the twentieth O2- site, O2- is bonded to three Zr4+ and one Nb5+ atom to form a mixture of distorted edge and corner-sharing OZr3Nb tetrahedra. In the twenty-first O2- site, O2- is bonded in a 3-coordinate geometry to two Zr4+ and one Nb5+ atom. In the twenty-second O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to two Zr4+ and one Nb5+ atom. In the twenty-third O2- site, O2- is bonded to three Zr4+ and one Nb5+ atom to form a mixture of distorted edge and corner-sharing OZr3Nb tetrahedra. In the twenty-fourth O2- site, O2- is bonded to three Zr4+ and one Nb5+ atom to form a mixture of edge and corner-sharing OZr3Nb tetrahedra. In the twenty-fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Zr4+ and one Nb5+ atom. In the twenty-sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Zr4+ atoms. In the twenty-seventh O2- site, O2- is bonded to three Zr4+ and one Nb5+ atom to form a mixture of edge and corner-sharing OZr3Nb tetrahedra. In the twenty-eighth O2- site, O2- is bonded to three Zr4+ and one Nb5+ atom to form a mixture of edge and corner-sharing OZr3Nb tetrahedra. In the twenty-ninth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Zr4+ and one Nb5+ atom. In the thirtieth O2- site, O2- is bonded in a trigonal planar geometry to two Zr4+ and one Nb5+ atom. In the thirty-first O2- site, O2- is bonded in a 3-coordinate geometry to three Zr4+ and one Nb5+ atom. In the thirty-second O2- site, O2- is bonded in a 3-coordinate geometry to three Zr4+ and one Nb5+ atom. In the thirty-third O2- site, O2- is bonded in a 3-coordinate geometry to two Zr4+ and one Nb5+ atom. In the thirty-fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Zr4+ atoms.