Revealing uranium tetrafluoride microrods†

Anhydrous and hydrated UF₄ microrods (5–25 μm) were prepared from the reactions of UO₂ microrods (5–15 μm) with HF(g), produced from the decomposition of silver bifluoride (AgHF₂, SBF). In order to optimize the preparation of UF₄ mr, several experimental parameters including atmosphere (air or N₂), temperature (150 or 250 °C) and amount of SBF were evaluated. In all reactions, rodlike morphologies were retained. At 250 °C, the reaction products always consist of an anhydrous UF₄/hydrated UF₄ mixture, while at 150 °C only hydrated UF₄ was detected. Anhydrous UF₄ microrods were obtained by dehydration of the anhydrous UF₄/hydated UF₄ mixture using TGA-DSC. Changing the atmosphere from air to N₂ or reducing the amount of SBF by half did not affect the nature of the reaction products.