DOE OSTI2020
Na2CeO3 is High Pressure (4-7GPa) Tellurium-derived structured and crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are seven inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with three CeO6 octahedra, edges with four CeO6 octahedra, and edges with five NaO6 octahedra. The corner-sharing octahedra tilt angles range from 10–21°. There are a spread of Na–O bond distances ranging from 2.35–2.51 Å. In the second Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.28–2.68 Å. In the third Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.44–2.52 Å. In the fourth Na1+ site, Na1+ is bonded to six O2- atoms to form distorted NaO6 octahedra that share corners with five CeO6 octahedra, edges with four CeO6 octahedra, and edges with five NaO6 octahedra. The corner-sharing octahedra tilt angles range from 3–11°. There are a spread of Na–O bond distances ranging from 2.33–2.57 Å. In the fifth Na1+ site, Na1+ is bonded to six O2- atoms to form distorted NaO6 octahedra that share corners with four CeO6 octahedra, edges with four NaO6 octahedra, and edges with four CeO6 octahedra. The corner-sharing octahedra tilt angles range from 10–14°. There are a spread of Na–O bond distances ranging from 2.27–2.52 Å. In the sixth Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.37–2.62 Å. In the seventh Na1+ site, Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with four CeO6 octahedra, edges with four NaO6 octahedra, and edges with four CeO6 octahedra. The corner-sharing octahedra tilt angles range from 11–15°. There are a spread of Na–O bond distances ranging from 2.36–2.54 Å. There are four inequivalent Ce4+ sites. In the first Ce4+ site, Ce4+ is bonded to six O2- atoms to form distorted CeO6 octahedra that share corners with five NaO6 octahedra, edges with four NaO6 octahedra, and edges with four CeO6 octahedra. The corner-sharing octahedra tilt angles range from 3–15°. There are a spread of Ce–O bond distances ranging from 2.21–2.38 Å. In the second Ce4+ site, Ce4+ is bonded to six O2- atoms to form distorted CeO6 octahedra that share corners with four NaO6 octahedra, edges with three CeO6 octahedra, and edges with four NaO6 octahedra. The corner-sharing octahedra tilt angles range from 11–21°. There are a spread of Ce–O bond distances ranging from 2.08–2.47 Å. In the third Ce4+ site, Ce4+ is bonded to six O2- atoms to form CeO6 octahedra that share corners with six NaO6 octahedra, edges with three CeO6 octahedra, and edges with six NaO6 octahedra. The corner-sharing octahedra tilt angles range from 8–11°. There are a spread of Ce–O bond distances ranging from 2.23–2.30 Å. In the fourth Ce4+ site, Ce4+ is bonded to six O2- atoms to form CeO6 octahedra that share corners with four NaO6 octahedra, edges with three CeO6 octahedra, and edges with six NaO6 octahedra. The corner-sharing octahedral tilt angles are 11°. There are a spread of Ce–O bond distances ranging from 2.26–2.30 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a 6-coordinate geometry to five Na1+ and one Ce4+ atom. In the second O2- site, O2- is bonded in a 6-coordinate geometry to four Na1+ and two Ce4+ atoms. In the third O2- site, O2- is bonded to three Na1+ and three Ce4+ atoms to form a mixture of edge and corner-sharing ONa3Ce3 octahedra. The corner-sharing octahedra tilt angles range from 0–15°. In the fourth O2- site, O2- is bonded to four Na1+ and two Ce4+ atoms to form distorted ONa4Ce2 octahedra that share corners with four ONa3Ce3 octahedra and edges with eight ONa4Ce2 octahedra. The corner-sharing octahedra tilt angles range from 7–9°. In the fifth O2- site, O2- is bonded to four Na1+ and two Ce4+ atoms to form distorted ONa4Ce2 octahedra that share corners with three ONa4Ce2 octahedra and edges with eight ONa3Ce3 octahedra. The corner-sharing octahedra tilt angles range from 3–12°. In the sixth O2- site, O2- is bonded to four Na1+ and two Ce4+ atoms to form a mixture of distorted edge and corner-sharing ONa4Ce2 octahedra. The corner-sharing octahedra tilt angles range from 6–12°. In the seventh O2- site, O2- is bonded to four Na1+ and two Ce4+ atoms to form distorted ONa4Ce2 octahedra that share corners with three ONa4Ce2 octahedra and edges with nine ONa3Ce3 octahedra. The corner-sharing octahedra tilt angles range from 6–9°. In the eighth O2- site, O2- is bonded in a 6-coordinate geometry to four Na1+ and two Ce4+ atoms. In the ninth O2- site, O2- is bonded to four Na1+ and two Ce4+ atoms to form a mixture of edge and corner-sharing ONa4Ce2 octahedra. The corner-sharing octahedra tilt angles range from 0–15°.