DOI: 10.17188/1689804
title: Materials Data on K6Ba2CaU6O24 by Materials Project

description: K6Ba2CaU6O24 crystallizes in the orthorhombic Cmmm space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded to twelve O2- atoms to form KO12 cuboctahedra that share corners with two equivalent BaO12 cuboctahedra, corners with ten KO12 cuboctahedra, faces with six KO12 cuboctahedra, faces with two equivalent CaO6 octahedra, and faces with six UO6 octahedra. There are a spread of K–O bond distances ranging from 3.08–3.13 Å. In the second K1+ site, K1+ is bonded to twelve O2- atoms to form KO12 cuboctahedra that share corners with four equivalent BaO12 cuboctahedra, corners with eight KO12 cuboctahedra, faces with two equivalent BaO12 cuboctahedra, faces with four KO12 cuboctahedra, a faceface with one CaO6 octahedra, and faces with six UO6 octahedra. There are a spread of K–O bond distances ranging from 3.01–3.25 Å. Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with two equivalent BaO12 cuboctahedra, corners with ten KO12 cuboctahedra, faces with two equivalent BaO12 cuboctahedra, faces with four equivalent KO12 cuboctahedra, and faces with six UO6 octahedra. There are a spread of Ba–O bond distances ranging from 3.02–3.12 Å. Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six UO6 octahedra and faces with eight KO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are four shorter (2.36 Å) and two longer (2.40 Å) Ca–O bond lengths. 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 CaO6 octahedra, corners with four UO6 octahedra, faces with two equivalent BaO12 cuboctahedra, and faces with six KO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 1–6°. There are a spread of U–O bond distances ranging from 1.92–2.20 Å. In the second U6+ site, U6+ is bonded to six O2- atoms to form UO6 octahedra that share corners with four equivalent UO6 octahedra, faces with four equivalent KO12 cuboctahedra, and faces with four equivalent BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 6°. There are two shorter (1.91 Å) and four longer (2.20 Å) U–O bond lengths. In the third U6+ site, U6+ is bonded to six O2- atoms to form UO6 octahedra that share corners with two equivalent CaO6 octahedra, corners with four equivalent UO6 octahedra, and faces with eight KO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are two shorter (1.96 Å) and four longer (2.18 Å) U–O bond lengths. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to three K1+, one Ba2+, and two equivalent U6+ atoms. In the second O2- site, O2- is bonded in a distorted linear geometry to four K1+, one Ca2+, and one U6+ atom. In the third O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent K1+, two equivalent Ba2+, and one U6+ atom. In the fourth O2- site, O2- is bonded in a distorted linear geometry to four K1+, one Ca2+, and one U6+ atom. In the fifth O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent K1+, two equivalent Ba2+, and one U6+ atom. In the sixth O2- site, O2- is bonded in a distorted linear geometry to four K1+ and two U6+ atoms. In the seventh O2- site, O2- is bonded in a distorted linear geometry to two equivalent K1+, two equivalent Ba2+, and two U6+ atoms.