DOI: 10.17188/1743376
title: Materials Data on Na6Ca3U2O12 by Materials Project

description: Na6Ca3U2O12 crystallizes in the monoclinic C2 space group. The structure is three-dimensional. there are six inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with two equivalent CaO6 octahedra, corners with two equivalent UO6 octahedra, edges with two equivalent UO6 octahedra, edges with four CaO6 octahedra, and edges with six NaO6 octahedra. The corner-sharing octahedra tilt angles range from 0–14°. There are a spread of Na–O bond distances ranging from 2.31–2.73 Å. In the second Na1+ site, Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with two equivalent UO6 octahedra, corners with four CaO6 octahedra, edges with two equivalent CaO6 octahedra, edges with two equivalent UO6 octahedra, and edges with six NaO6 octahedra. The corner-sharing octahedra tilt angles range from 9–16°. There are a spread of Na–O bond distances ranging from 2.43–2.84 Å. In the third Na1+ site, Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with two equivalent NaO6 octahedra, corners with two equivalent CaO6 octahedra, corners with two equivalent UO6 octahedra, edges with two equivalent UO6 octahedra, edges with four CaO6 octahedra, and edges with five NaO6 octahedra. The corner-sharing octahedra tilt angles range from 4–20°. There are a spread of Na–O bond distances ranging from 2.38–2.70 Å. In the fourth Na1+ site, Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with two equivalent NaO6 octahedra, corners with two equivalent UO6 octahedra, edges with two equivalent UO6 octahedra, edges with three CaO6 octahedra, and edges with five NaO6 octahedra. The corner-sharing octahedra tilt angles range from 7–20°. There are a spread of Na–O bond distances ranging from 2.32–2.68 Å. In the fifth Na1+ site, Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with two equivalent NaO6 octahedra, corners with two equivalent CaO6 octahedra, corners with two equivalent UO6 octahedra, edges with two equivalent UO6 octahedra, edges with five NaO6 octahedra, and edges with five CaO6 octahedra. The corner-sharing octahedra tilt angles range from 5–14°. There are a spread of Na–O bond distances ranging from 2.51–2.55 Å. In the sixth Na1+ site, Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with two equivalent NaO6 octahedra, corners with two equivalent CaO6 octahedra, corners with two equivalent UO6 octahedra, edges with two equivalent UO6 octahedra, edges with three CaO6 octahedra, and edges with five NaO6 octahedra. The corner-sharing octahedra tilt angles range from 10–22°. There are two shorter (2.53 Å) and four longer (2.58 Å) Na–O bond lengths. There are three inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with four NaO6 octahedra, edges with two equivalent CaO6 octahedra, edges with three UO6 octahedra, and edges with seven NaO6 octahedra. The corner-sharing octahedra tilt angles range from 10–14°. There are a spread of Ca–O bond distances ranging from 2.28–2.40 Å. In the second Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with two equivalent CaO6 octahedra, corners with four NaO6 octahedra, edges with three UO6 octahedra, and edges with seven NaO6 octahedra. The corner-sharing octahedra tilt angles range from 14–22°. There are a spread of Ca–O bond distances ranging from 2.33–2.43 Å. In the third Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with two equivalent CaO6 octahedra, corners with four NaO6 octahedra, edges with two equivalent CaO6 octahedra, edges with three UO6 octahedra, and edges with seven NaO6 octahedra. The corner-sharing octahedra tilt angles range from 9–14°. There are two shorter (2.37 Å) and four longer (2.40 Å) Ca–O bond lengths. There are two inequivalent U6+ sites. In the first U6+ site, U6+ is bonded to six O2- atoms to form UO6 octahedra that share corners with six NaO6 octahedra, edges with five CaO6 octahedra, and edges with six NaO6 octahedra. The corner-sharing octahedra tilt angles range from 0–7°. There are a spread of U–O bond distances ranging from 2.05–2.16 Å. In the second U6+ site, U6+ is bonded to six O2- atoms to form UO6 octahedra that share corners with six NaO6 octahedra, edges with four CaO6 octahedra, and edges with six NaO6 octahedra. The corner-sharing octahedra tilt angles range from 5–10°. There are a spread of U–O bond distances ranging from 2.05–2.21 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded to three Na1+, one Ca2+, and one U6+ atom to form distorted ONa3CaU square pyramids that share corners with two equivalent ONa3Ca2U octahedra, corners with seven ONa3CaU square pyramids, edges with five ONa3Ca2U octahedra, and edges with three ONa3CaU square pyramids. The corner-sharing octahedra tilt angles range from 9–11°. In the second O2- site, O2- is bonded to three Na1+, one Ca2+, and one U6+ atom to form distorted ONa3CaU square pyramids that share corners with two equivalent ONa3Ca2U octahedra, corners with seven ONa3CaU square pyramids, edges with five ONa3Ca2U octahedra, and edges with three ONa3CaU square pyramids. The corner-sharing octahedra tilt angles range from 4–8°. In the third O2- site, O2- is bonded to three Na1+, two Ca2+, and one U6+ atom to form distorted ONa3Ca2U octahedra that share corners with two equivalent ONa3Ca2U octahedra, corners with four ONa3CaU square pyramids, edges with ten ONa3Ca2U octahedra, and edges with two ONa3CaU square pyramids. The corner-sharing octahedra tilt angles range from 6–12°. In the fourth O2- site, O2- is bonded to three Na1+, one Ca2+, and one U6+ atom to form ONa3CaU square pyramids that share corners with four ONa3Ca2U octahedra, corners with five ONa3CaU square pyramids, edges with two ONa3Ca2U octahedra, and edges with six ONa3CaU square pyramids. The corner-sharing octahedra tilt angles range from 3–13°. In the fifth O2- site, O2- is bonded to three Na1+, two Ca2+, and one U6+ atom to form ONa3Ca2U octahedra that share corners with four ONa3Ca2U octahedra, corners with two equivalent ONa3CaU square pyramids, edges with seven ONa3Ca2U octahedra, and edges with five ONa3CaU square pyramids. The corner-sharing octahedra tilt angles range from 4–9°. In the sixth O2- site, O2- is bonded to three Na1+, two Ca2+, and one U6+ atom to form distorted ONa3Ca2U octahedra that share corners with four ONa3Ca2U octahedra, corners with two equivalent ONa3CaU square pyramids, edges with seven ONa3Ca2U octahedra, and edges with five ONa3CaU square pyramids. The corner-sharing octahedra tilt angles range from 1–9°.