Applications of Alkali Metal Hydroxide Hydrofluxes to the Synthesis of Single-Crystal Ternary Actinide Oxides

Hydrofluxes are hydrated salts with melting points well below that of the dehydrated salt and boiling points well above that of water, affording a reaction medium, in which mild temperatures and pressures can be accessed for the synthesis of materials. Herein, the use of alkali metal hydroxide hydrofluxes for the synthesis of single crystal alpha-Na2NpO4 is described, and the single crystal X-ray structure of alpha-Na2NpO4, along with its X-ray absorption spectra and vibrational spectra, is reported. The ability to synthesize complex oxides of the actinides, in particular, transuranium materials, under mild conditions will serve to advance our ability to explore the structure-property relationships of the f elements.