Pf_6~- Hydrolysis As A Route To Unique Uranium Phosphate Materials

摘要

An uranium phosphate fluoride with a unique pentameric secondary building unit is prepared under hydrothermal conditions with UO_2(NO_3)_2 6H_2O, PF_6~- and 4,4'-bipyridine; the single-crystal structure is determined.rnMetal phosphate chemistry has been explored extensively as related to areas such as materials chemistry1 and mineralogy. In particular, uranyl (UO_2~(2+)) phosphate phases have been studied owing to their ubiquity in actinide-bearing minerals, structural diversity, and potential applications and relevance in areas such as the long-term stewardship of spent nuclear fuel. The insolubility of uranium phosphates, and indeed uranium phosphate fluorides, makes the synthesis of new crystalline products difficult as amorphous or micro-crystalline products often result when phosphate is immediately available to uranium. As a result, there is a limited catalogue of synthetic uranium phosphate compounds. Traditional hydrothermal synthesis of these materials generally involves phosphate anions that are introduced via preformed alkali metal phosphates or phosphoric acid. We report herein an alternative route, namely the hydrolysis of the hexafluoro-phosphate anion (PF_6~-) to yield phosphate bearing phases.