DOI: 10.17188/1306989
title: Materials Data on Na8Gd2O7 by Materials Project

description: Na8Gd2O7 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are eight inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to four O2- atoms to form distorted NaO4 tetrahedra that share a cornercorner with one NaO6 octahedra, corners with four GdO4 tetrahedra, corners with three NaO5 trigonal bipyramids, corners with two equivalent NaO4 trigonal pyramids, an edgeedge with one NaO6 octahedra, an edgeedge with one NaO4 tetrahedra, and an edgeedge with one NaO5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 88°. There are a spread of Na–O bond distances ranging from 2.26–2.64 Å. In the second Na1+ site, Na1+ is bonded to five O2- atoms to form distorted NaO5 trigonal bipyramids that share a cornercorner with one NaO6 octahedra, corners with two NaO4 tetrahedra, corners with four GdO4 tetrahedra, corners with two equivalent NaO5 trigonal bipyramids, corners with two equivalent NaO4 trigonal pyramids, edges with two equivalent NaO6 octahedra, an edgeedge with one NaO4 tetrahedra, an edgeedge with one GdO4 tetrahedra, and edges with two NaO5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 46°. There are a spread of Na–O bond distances ranging from 2.30–2.80 Å. In the third Na1+ site, Na1+ is bonded to six O2- atoms to form distorted NaO6 octahedra that share corners with two equivalent NaO6 octahedra, corners with three NaO4 tetrahedra, a cornercorner with one NaO5 trigonal bipyramid, an edgeedge with one NaO4 tetrahedra, edges with four GdO4 tetrahedra, edges with three NaO5 trigonal bipyramids, and an edgeedge with one NaO4 trigonal pyramid. The corner-sharing octahedral tilt angles are 34°. There are a spread of Na–O bond distances ranging from 2.46–2.88 Å. In the fourth Na1+ site, Na1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Na–O bond distances ranging from 2.31–2.81 Å. In the fifth Na1+ site, Na1+ is bonded to five O2- atoms to form distorted NaO5 trigonal bipyramids that share a cornercorner with one GdO4 tetrahedra, corners with three NaO4 tetrahedra, corners with four NaO5 trigonal bipyramids, a cornercorner with one NaO4 trigonal pyramid, an edgeedge with one NaO6 octahedra, edges with two NaO4 tetrahedra, edges with two equivalent GdO4 tetrahedra, an edgeedge with one NaO5 trigonal bipyramid, and an edgeedge with one NaO4 trigonal pyramid. There are a spread of Na–O bond distances ranging from 2.36–2.95 Å. In the sixth Na1+ site, Na1+ is bonded in a 3-coordinate geometry to four O2- atoms. There are a spread of Na–O bond distances ranging from 2.21–3.05 Å. In the seventh Na1+ site, Na1+ is bonded to four O2- atoms to form NaO4 tetrahedra that share corners with two equivalent NaO6 octahedra, corners with four GdO4 tetrahedra, corners with two NaO5 trigonal bipyramids, a cornercorner with one NaO4 trigonal pyramid, an edgeedge with one NaO4 tetrahedra, edges with two NaO5 trigonal bipyramids, and an edgeedge with one NaO4 trigonal pyramid. The corner-sharing octahedra tilt angles range from 21–91°. There are a spread of Na–O bond distances ranging from 2.32–2.61 Å. In the eighth Na1+ site, Na1+ is bonded to four O2- atoms to form distorted NaO4 trigonal pyramids that share corners with two GdO4 tetrahedra, corners with three NaO4 tetrahedra, corners with three NaO5 trigonal bipyramids, an edgeedge with one NaO6 octahedra, an edgeedge with one NaO4 tetrahedra, an edgeedge with one GdO4 tetrahedra, and an edgeedge with one NaO5 trigonal bipyramid. There are a spread of Na–O bond distances ranging from 2.33–2.52 Å. There are two inequivalent Gd3+ sites. In the first Gd3+ site, Gd3+ is bonded to four O2- atoms to form GdO4 tetrahedra that share a cornercorner with one GdO4 tetrahedra, corners with four NaO4 tetrahedra, corners with two equivalent NaO5 trigonal bipyramids, a cornercorner with one NaO4 trigonal pyramid, edges with two equivalent NaO6 octahedra, and edges with three NaO5 trigonal bipyramids. There are a spread of Gd–O bond distances ranging from 2.12–2.21 Å. In the second Gd3+ site, Gd3+ is bonded to four O2- atoms to form GdO4 tetrahedra that share a cornercorner with one GdO4 tetrahedra, corners with four NaO4 tetrahedra, corners with three NaO5 trigonal bipyramids, a cornercorner with one NaO4 trigonal pyramid, edges with two equivalent NaO6 octahedra, and an edgeedge with one NaO4 trigonal pyramid. There are a spread of Gd–O bond distances ranging from 2.15–2.20 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded to five Na1+ and one Gd3+ atom to form a mixture of edge and corner-sharing ONa5Gd octahedra. The corner-sharing octahedral tilt angles are 63°. In the second O2- site, O2- is bonded in a 6-coordinate geometry to four Na1+ and two Gd3+ atoms. In the third O2- site, O2- is bonded to five Na1+ and one Gd3+ atom to form a mixture of distorted edge and corner-sharing ONa5Gd octahedra. The corner-sharing octahedra tilt angles range from 9–63°. In the fourth O2- site, O2- is bonded in a 7-coordinate geometry to six Na1+ and one Gd3+ atom. In the fifth O2- site, O2- is bonded to five Na1+ and one Gd3+ atom to form a mixture of distorted edge and corner-sharing ONa5Gd octahedra. The corner-sharing octahedral tilt angles are 9°. In the sixth O2- site, O2- is bonded in a 6-coordinate geometry to five Na1+ and one Gd3+ atom. In the seventh O2- site, O2- is bonded in a 7-coordinate geometry to six Na1+ and one Gd3+ atom.