DOE OSTI2020
Pb3U11O36 crystallizes in the orthorhombic Pmmn space group. The structure is three-dimensional. there are six inequivalent U6+ sites. In the first U6+ site, U6+ is bonded to seven O2- atoms to form distorted UO7 pentagonal bipyramids that share corners with two equivalent UO6 octahedra, corners with two equivalent PbO7 pentagonal bipyramids, edges with two equivalent UO6 octahedra, and edges with two equivalent UO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 33°. There are a spread of U–O bond distances ranging from 1.85–2.52 Å. In the second U6+ site, U6+ is bonded to seven O2- atoms to form distorted UO7 pentagonal bipyramids that share corners with two UO6 octahedra, a cornercorner with one UO7 pentagonal bipyramid, corners with two equivalent PbO7 pentagonal bipyramids, an edgeedge with one UO6 octahedra, and edges with two UO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 35–48°. There are a spread of U–O bond distances ranging from 1.86–2.48 Å. In the third U6+ site, U6+ is bonded to seven O2- atoms to form distorted UO7 pentagonal bipyramids that share corners with four UO6 octahedra, a cornercorner with one UO7 pentagonal bipyramid, an edgeedge with one UO6 octahedra, an edgeedge with one UO7 pentagonal bipyramid, and an edgeedge with one PbO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 3–48°. There are a spread of U–O bond distances ranging from 1.93–2.52 Å. In the fourth U6+ site, U6+ is bonded to six O2- atoms to form UO6 octahedra that share corners with three UO6 octahedra, corners with three UO7 pentagonal bipyramids, and edges with two UO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 0–33°. There are a spread of U–O bond distances ranging from 1.99–2.16 Å. In the fifth U6+ site, U6+ is bonded to six O2- atoms to form UO6 octahedra that share corners with four UO6 octahedra, corners with two PbO7 pentagonal bipyramids, and edges with two PbO7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 0–26°. There are a spread of U–O bond distances ranging from 1.90–2.25 Å. In the sixth U6+ site, U6+ is bonded to six O2- atoms to form UO6 octahedra that share a cornercorner with one UO6 octahedra, a cornercorner with one PbO7 pentagonal bipyramid, corners with four UO7 pentagonal bipyramids, an edgeedge with one UO7 pentagonal bipyramid, and an edgeedge with one PbO7 pentagonal bipyramid. The corner-sharing octahedral tilt angles are 22°. There are a spread of U–O bond distances ranging from 1.99–2.31 Å. There are two inequivalent Pb2+ sites. In the first Pb2+ site, Pb2+ is bonded to seven O2- atoms to form distorted PbO7 pentagonal bipyramids that share corners with two equivalent UO6 octahedra, corners with two equivalent UO7 pentagonal bipyramids, edges with two equivalent UO6 octahedra, and edges with two equivalent PbO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 37°. There are a spread of Pb–O bond distances ranging from 2.46–2.74 Å. In the second Pb2+ site, Pb2+ is bonded to seven O2- atoms to form distorted PbO7 pentagonal bipyramids that share corners with two UO6 octahedra, corners with two equivalent UO7 pentagonal bipyramids, edges with two UO6 octahedra, an edgeedge with one UO7 pentagonal bipyramid, and an edgeedge with one PbO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 35–41°. There are a spread of Pb–O bond distances ranging from 2.44–2.79 Å. There are sixteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to one U6+ and one Pb2+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to one U6+ and one Pb2+ atom. In the third O2- site, O2- is bonded in a linear geometry to two U6+ atoms. In the fourth O2- site, O2- is bonded in a linear geometry to two U6+ atoms. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to three U6+ atoms. In the sixth O2- site, O2- is bonded in a 1-coordinate geometry to three U6+ atoms. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to two U6+ and one Pb2+ atom. In the eighth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent U6+ and one Pb2+ atom. In the ninth O2- site, O2- is bonded in a 2-coordinate geometry to three U6+ atoms. In the tenth O2- site, O2- is bonded in a distorted trigonal planar geometry to three U6+ atoms. In the eleventh O2- site, O2- is bonded in a 1-coordinate geometry to two U6+ and one Pb2+ atom. In the twelfth O2- site, O2- is bonded in a distorted single-bond geometry to one U6+ and two Pb2+ atoms. In the thirteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to three U6+ atoms. In the fourteenth O2- site, O2- is bonded in a linear geometry to two U6+ atoms. In the fifteenth O2- site, O2- is bonded in a 1-coordinate geometry to two U6+ and one Pb2+ atom. In the sixteenth O2- site, O2- is bonded in a distorted single-bond geometry to one U6+ and two Pb2+ atoms.