Materials Data on K6Ba2CaU6O24 by Materials Project
K6Ba2CaU6O24 crystallizes in the orthorhombic Cmme space group. The structure is three-dimensional. there are four inequivalent K1+ sites. In the first 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 3.06–3.16 Å. In the second K1+ site, K1+ is bonded to twelve O2- atoms to form KO12 cuboctahedra that share corners with twelve KO12 cuboctahedra, faces with six KO12 cuboctahedra, faces with two equivalent CaO6 octahedra, and faces with six UO6 octahedra. There are six shorter (3.08 Å) and six longer (3.09 Å) K–O bond lengths. In the third K1+ site, K1+ is bonded to twelve O2- atoms to form KO12 cuboctahedra that share a cornercorner with one BaO12 cuboctahedra, corners with eleven 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 3.07–3.15 Å. In the fourth K1+ site, K1+ is bonded to twelve O2- atoms to form KO12 cuboctahedra that share corners with four KO12 cuboctahedra, corners with eight equivalent BaO12 cuboctahedra, faces with two equivalent KO12 cuboctahedra, faces with four equivalent BaO12 cuboctahedra, and faces with six UO6 octahedra. There are a spread of K–O bond distances ranging from 3.08–3.16 Å. Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with three equivalent BaO12 cuboctahedra, corners with nine KO12 cuboctahedra, faces with two equivalent BaO12 cuboctahedra, faces with four KO12 cuboctahedra, and faces with six UO6 octahedra. There are a spread of Ba–O bond distances ranging from 3.01–3.11 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 two shorter (2.36 Å) and four longer (2.39 Å) Ca–O bond lengths. There are six 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 1.91–2.19 Å. In the second U6+ site, U6+ is bonded to six O2- atoms to form UO6 octahedra that share corners with two equivalent CaO6 octahedra, corners with four UO6 octahedra, and faces with eight KO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of U–O bond distances ranging from 1.97–2.18 Å. 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 UO6 octahedra, and faces with eight KO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are a spread of U–O bond distances ranging from 1.97–2.17 Å. In the fourth U6+ site, U6+ is bonded to six O2- atoms to form UO6 octahedra that share corners with four UO6 octahedra, faces with four equivalent KO12 cuboctahedra, and faces with four equivalent BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–4°. There are a spread of U–O bond distances ranging from 1.91–2.19 Å. In the fifth U6+ site, U6+ is bonded to six O2- atoms to form UO6 octahedra that share corners with four UO6 octahedra, faces with four KO12 cuboctahedra, and faces with four equivalent BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 4–6°. There are a spread of U–O bond distances ranging from 1.90–2.20 Å. In the sixth U6+ site, U6+ is bonded to six O2- atoms to form UO6 octahedra that share corners with two equivalent CaO6 octahedra, corners with four UO6 octahedra, and faces with eight KO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of U–O bond distances ranging from 1.97–2.18 Å. There are fourteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to two equivalent K1+, two equivalent Ba2+, and one U6+ atom. In the second O2- site, O2- is bonded in a distorted linear geometry to two equivalent K1+, two equivalent Ba2+, and two U6+ atoms. In the third O2- site, O2- is bonded in a distorted linear geometry to three K1+, one Ba2+, and two equivalent U6+ atoms. 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 linear geometry to four K1+, one Ca2+, 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 four K1+ and two U6+ atoms. In the eighth O2- site, O2- is bonded in a distorted linear geometry to four K1+ and two U6+ atoms. In the ninth O2- site, O2- is bonded in a distorted linear geometry to four K1+, one Ca2+, and one U6+ atom. In the tenth O2- site, O2- is bonded in a single-bond geometry to two equivalent K1+, two equivalent Ba2+, and one U6+ atom. In the eleventh O2- site, O2- is bonded in a distorted linear geometry to two equivalent K1+, two equivalent Ba2+, and two U6+ atoms. In the twelfth O2- site, O2- is bonded in a distorted linear geometry to two equivalent K1+, two equivalent Ba2+, and two equivalent U6+ atoms. In the thirteenth O2- site, O2- is bonded in a single-bond geometry to two K1+, two equivalent Ba2+, and one U6+ atom. In the fourteenth O2- site, O2- is bonded in a distorted linear geometry to four K1+ and two equivalent U6+ atoms. There are two shorter (3.07 Å) and two longer (3.08 Å) O–K bond lengths. Both O–U bond lengths are 2.18 Å.