Targeting complex plutonium oxides by combining crystal chemical reasoning with density-functional theory calculations: the quaternary plutonium oxide Cs2PuSi6O15

Kristen A Pace; Vladislav V Klepov; Matthew S Christian; Gregory Morrison; Travis K Deason; Ceren Kutahyali Aslani; Theodore M Besmann; David P Diprete; Jake W Amoroso; Hans-Conrad Zur Loye

doi:10.1039/d0cc02674c

Targeting complex plutonium oxides by combining crystal chemical reasoning with density-functional theory calculations: the quaternary plutonium oxide Cs₂PuSi₆O₁₅

Chem Commun (Camb). 2020 Aug 19;56(66):9501-9504. doi: 10.1039/d0cc02674c.

Affiliations

¹ Center for Hierarchical Waste form Materials, Columbia, South Carolina 29208, USA. zurloye@mailbox.sc.edu and Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, USA.
² Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, USA.
³ Center for Hierarchical Waste form Materials, Columbia, South Carolina 29208, USA. zurloye@mailbox.sc.edu and Department of Mechanical Engineering, University of South Carolina, Columbia, South Carolina 29208, USA.
⁴ Savannah River National Laboratory, Aiken, South Carolina 29803, USA.
⁵ Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, USA and Department of Mechanical Engineering, University of South Carolina, Columbia, South Carolina 29208, USA.
⁶ Center for Hierarchical Waste form Materials, Columbia, South Carolina 29208, USA. zurloye@mailbox.sc.edu and Savannah River National Laboratory, Aiken, South Carolina 29803, USA.

PMID: 32685942
DOI: 10.1039/d0cc02674c

Abstract

The stability of the novel Pu(iv) silicate, Cs2PuSi6O15, was predicted from a combination of crystal chemical reasoning and DFT calculations and confirmed by its synthesis via flux crystal growth. Formation enthalpies of the A2MSi6O15 (A = Na-Cs; M = Ce, Th, U-Pu) compositional family were calculated and indicated the Cs-containing phases should preferentially form in the Cmc21 structure type, consistent with previous experimental findings and the novel phases produced in this work, Cs2PuSi6O15 and Cs2CeSi6O15. The formation enthalpies of a second set of compositions, A2MSi3O9, were also calculated and a comparison between the two compositional families correctly predicted A2MSi6O15 to be on average more stable than A2MSi3O9.