Concepedia

Publication | Closed Access

Crystallization of A<sub>3</sub>Ln(BO<sub>3</sub>)<sub>2</sub> (A = Na, K; Ln = Lanthanide) from a Boric Acid Containing Hydroxide Melt: Synthesis and Investigation of Lanthanide Borates as Potential Nuclear Waste Forms

DOI

14

Citations

37

References

2022

Year

Adrian T. Hines, Gregory Morrison, Hunter B. Tisdale, Mark D. Smith, Theodore M. Besmann, Amir Mofrad, Mina Aziziha, Ronald E. Booth, Kai Sun, Gary S. Was,
Inorganic Chemistry

Abstract

A series of alkali metal rare-earth borates were prepared via high-temperature flux crystal growth, and their structures were characterized by single crystal X-ray diffraction (SXRD). Na<sub>3</sub>Ln(BO<sub>3</sub>)<sub>2</sub> (Ln = La-Lu) crystallize in the monoclinic space group <i>P</i>2<sub>1</sub>/<i>n</i>, the potassium series K<sub>3</sub>Ln(BO<sub>3</sub>)<sub>2</sub> (Ln = La-Tb) crystallize in the orthorhombic space group <i>Pnma,</i> while the Ln = Dy, Ho, Tm, Yb analogues crystallize in the orthorhombic space group <i>Pnnm</i>. To demonstrate the generality of this synthetic technique, high-entropy oxide (HEO) compositions K<sub>3</sub>Nd<sub>0.15(1)</sub>Eu<sub>0.20(1)</sub>Gd<sub>0.20(1)</sub>Dy<sub>0.22(1)</sub>Ho<sub>0.23(1)</sub>(BO<sub>3</sub>)<sub>2</sub> and K<sub>3</sub>Nd<sub>0.26(1)</sub>Eu<sub>0.29(1)</sub>Ho<sub>0.22(1)</sub>Tm<sub>0.14(1)</sub>Yb<sub>0.10(1)</sub>(BO<sub>3</sub>)<sub>2</sub> were obtained in single crystal form. Radiation damage investigations determined that these borates have a high radiation damage tolerance. To assess whether trivalent actinide analogues of Na<sub>3</sub>Ln(BO<sub>3</sub>)<sub>2</sub> and K<sub>3</sub>Ln(BO<sub>3</sub>)<sub>2</sub> would be stable, density functional theory was used to calculate their enthalpies of formation, which are favorable.

References

YearCitations

Page 1