DOI: 10.17188/1663589
title: Materials Data on Na5U5O18 by Materials Project

description: Na5U5O18 crystallizes in the monoclinic Cc space group. The structure is three-dimensional. there are five inequivalent Na sites. In the first Na site, Na is bonded in a 8-coordinate geometry to eight O atoms. There are a spread of Na–O bond distances ranging from 2.53–2.92 Å. In the second Na site, Na is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Na–O bond distances ranging from 2.41–2.70 Å. In the third Na site, Na is bonded in a 8-coordinate geometry to eight O atoms. There are a spread of Na–O bond distances ranging from 2.38–2.95 Å. In the fourth Na site, Na is bonded in a 8-coordinate geometry to eight O atoms. There are a spread of Na–O bond distances ranging from 2.44–2.94 Å. In the fifth Na site, Na is bonded to five O atoms to form distorted NaO5 trigonal bipyramids that share corners with two equivalent UO6 octahedra and a cornercorner with one UO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 49–56°. There are a spread of Na–O bond distances ranging from 2.41–2.56 Å. There are five inequivalent U sites. In the first U site, U is bonded to seven O atoms to form distorted UO7 pentagonal bipyramids that share a cornercorner with one UO6 octahedra, a cornercorner with one NaO5 trigonal bipyramid, an edgeedge with one UO6 octahedra, and an edgeedge with one UO7 pentagonal bipyramid. The corner-sharing octahedral tilt angles are 41°. There are a spread of U–O bond distances ranging from 1.89–2.49 Å. In the second U site, U is bonded to seven O atoms to form distorted UO7 pentagonal bipyramids that share a cornercorner with one UO6 octahedra, an edgeedge with one UO6 octahedra, and an edgeedge with one UO7 pentagonal bipyramid. The corner-sharing octahedral tilt angles are 41°. There are a spread of U–O bond distances ranging from 1.88–2.49 Å. In the third U site, U is bonded to six O atoms to form UO6 octahedra that share corners with two UO7 pentagonal bipyramids, corners with two equivalent NaO5 trigonal bipyramids, and edges with two UO7 pentagonal bipyramids. There are a spread of U–O bond distances ranging from 1.89–2.20 Å. In the fourth U site, U is bonded in a 6-coordinate geometry to six O atoms. There are a spread of U–O bond distances ranging from 1.89–2.26 Å. In the fifth U site, U is bonded in a 6-coordinate geometry to six O atoms. There are a spread of U–O bond distances ranging from 1.89–2.26 Å. There are eighteen inequivalent O sites. In the first O site, O is bonded in a distorted trigonal planar geometry to one Na and three U atoms. In the second O site, O is bonded in a distorted trigonal planar geometry to one Na and three U atoms. In the third O site, O is bonded to three Na and one U atom to form distorted ONa3U tetrahedra that share corners with seven ONa3U tetrahedra, a cornercorner with one ONaU3 trigonal pyramid, and an edgeedge with one ONa3U tetrahedra. In the fourth O site, O is bonded in a 3-coordinate geometry to two Na and one U atom. In the fifth O site, O is bonded to three Na and one U atom to form distorted ONa3U tetrahedra that share corners with six ONa3U tetrahedra, a cornercorner with one ONaU3 trigonal pyramid, and edges with two equivalent ONa3U tetrahedra. In the sixth O site, O is bonded to three Na and one U atom to form distorted ONa3U tetrahedra that share corners with four ONa3U tetrahedra, a cornercorner with one ONaU3 trigonal pyramid, and edges with three ONa3U tetrahedra. In the seventh O site, O is bonded to three Na and one U atom to form distorted ONa3U tetrahedra that share corners with three ONa3U tetrahedra, a cornercorner with one ONaU3 trigonal pyramid, an edgeedge with one ONa3U tetrahedra, and an edgeedge with one ONaU3 trigonal pyramid. In the eighth O site, O is bonded to three Na and one U atom to form distorted ONa3U tetrahedra that share corners with two ONa3U tetrahedra, a cornercorner with one ONaU3 trigonal pyramid, an edgeedge with one ONa3U tetrahedra, and an edgeedge with one ONaU3 trigonal pyramid. In the ninth O site, O is bonded in a distorted bent 150 degrees geometry to two U atoms. In the tenth O site, O is bonded in a distorted bent 150 degrees geometry to two U atoms. In the eleventh O site, O is bonded to one Na and three U atoms to form distorted ONaU3 trigonal pyramids that share corners with three ONa3U tetrahedra, corners with two equivalent ONaU3 trigonal pyramids, and an edgeedge with one ONa3U tetrahedra. In the twelfth O site, O is bonded to one Na and three U atoms to form distorted ONaU3 trigonal pyramids that share corners with two ONa3U tetrahedra, corners with two equivalent ONaU3 trigonal pyramids, and an edgeedge with one ONa3U tetrahedra. In the thirteenth O site, O is bonded in a 4-coordinate geometry to three Na and one U atom. In the fourteenth O site, O is bonded in a 4-coordinate geometry to three Na and one U atom. In the fifteenth O site, O is bonded in a 4-coordinate geometry to three Na and one U atom. In the sixteenth O site, O is bonded in a 1-coordinate geometry to three Na and one U atom. In the seventeenth O site, O is bonded in a 4-coordinate geometry to one Na and three U atoms. In the eighteenth O site, O is bonded in a 4-coordinate geometry to one Na and three U atoms.