DOI: 10.17188/1730002
title: Materials Data on Cs4K3U3Si4O20F by Materials Project

description: Cs4K3U3Si4O20F crystallizes in the orthorhombic Cmc2_1 space group. The structure is three-dimensional. there are two inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded in a 7-coordinate geometry to six O2- and one F1- atom. There are a spread of Cs–O bond distances ranging from 3.14–3.36 Å. The Cs–F bond length is 2.92 Å. In the second Cs1+ site, Cs1+ is bonded in a 1-coordinate geometry to seven O2- and one F1- atom. There are a spread of Cs–O bond distances ranging from 3.09–3.57 Å. The Cs–F bond length is 2.94 Å. There are three inequivalent K1+ sites. In the first K1+ site, K1+ is bonded to seven O2- atoms to form distorted KO7 hexagonal pyramids that share a cornercorner with one KO7F hexagonal bipyramid, corners with two UO6 octahedra, corners with two equivalent SiO4 tetrahedra, edges with two equivalent UO6 octahedra, and edges with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 46–54°. There are a spread of K–O bond distances ranging from 2.63–3.05 Å. In the second K1+ site, K1+ is bonded to seven O2- and one F1- atom to form KO7F hexagonal bipyramids that share corners with three KO7 hexagonal pyramids, a cornercorner with one UO6 octahedra, edges with two equivalent UO6 octahedra, and edges with four SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 48°. There are a spread of K–O bond distances ranging from 2.78–3.00 Å. The K–F bond length is 3.16 Å. In the third K1+ site, K1+ is bonded to six O2- and one F1- atom to form distorted KO6F hexagonal pyramids that share corners with two equivalent KO7F hexagonal bipyramids, a cornercorner with one UO6 octahedra, corners with two equivalent SiO4 tetrahedra, edges with two equivalent UO6 octahedra, and edges with two equivalent SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 52°. There are a spread of K–O bond distances ranging from 2.77–3.08 Å. The K–F bond length is 3.14 Å. There are three inequivalent U6+ sites. In the first U6+ site, U6+ is bonded to six O2- atoms to form UO6 octahedra that share a cornercorner with one KO7F hexagonal bipyramid, a cornercorner with one KO6F hexagonal pyramid, corners with four SiO4 tetrahedra, and edges with two equivalent KO7 hexagonal pyramids. There are a spread of U–O bond distances ranging from 1.87–2.26 Å. In the second U6+ site, U6+ is bonded to six O2- atoms to form UO6 octahedra that share a cornercorner with one KO7 hexagonal pyramid, corners with four SiO4 tetrahedra, and edges with two equivalent KO7F hexagonal bipyramids. There are a spread of U–O bond distances ranging from 1.87–2.27 Å. In the third U6+ site, U6+ is bonded to six O2- atoms to form UO6 octahedra that share a cornercorner with one KO7 hexagonal pyramid, corners with four SiO4 tetrahedra, and edges with two equivalent KO6F hexagonal pyramids. There are a spread of U–O bond distances ranging from 1.87–2.28 Å. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one KO6F hexagonal pyramid, corners with three UO6 octahedra, a cornercorner with one SiO4 tetrahedra, an edgeedge with one KO7F hexagonal bipyramid, and an edgeedge with one KO7 hexagonal pyramid. The corner-sharing octahedra tilt angles range from 23–49°. There is three shorter (1.64 Å) and one longer (1.69 Å) Si–O bond length. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one KO7 hexagonal pyramid, corners with three UO6 octahedra, a cornercorner with one SiO4 tetrahedra, an edgeedge with one KO7F hexagonal bipyramid, and an edgeedge with one KO6F hexagonal pyramid. The corner-sharing octahedra tilt angles range from 26–51°. There is three shorter (1.64 Å) and one longer (1.69 Å) Si–O bond length. There are fourteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to one Cs1+, one K1+, one U6+, and one Si4+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one Cs1+, one K1+, one U6+, and one Si4+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to one Cs1+, one K1+, one U6+, and one Si4+ atom. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to two K1+ and two equivalent Si4+ atoms. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one U6+, and one Si4+ atom. In the sixth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two K1+ and two equivalent Si4+ atoms. In the seventh O2- site, O2- is bonded in a 1-coordinate geometry to one Cs1+, one K1+, one U6+, and one Si4+ atom. In the eighth O2- site, O2- is bonded in a 2-coordinate geometry to one Cs1+, one K1+, one U6+, and one Si4+ atom. In the ninth O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Cs1+, one K1+, and one U6+ atom. In the tenth O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Cs1+, one K1+, and one U6+ atom. In the eleventh O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Cs1+, one K1+, and one U6+ atom. In the twelfth O2- site, O2- is bonded in a single-bond geometry to four Cs1+ and one U6+ atom. In the thirteenth O2- site, O2- is bonded in a single-bond geometry to four Cs1+ and one U6+ atom. In the fourteenth O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Cs1+, one K1+, and one U6+ atom. F1- is bonded in an octahedral geometry to four Cs1+ and two K1+ atoms.