Thermal Stability and Products of Decomposition of Hydroxylaminate Uranyl Complexes

U(vi) hydrazinates: structural and thermal decomposition features

“…The ease of hydrazine removal from the structure of xUO 3 ÁyN 2 H 4 ÁzH 2 O can be explained not only by its high chemical reactivity, but also because of its presence in the ] also decomposes at 185 1C, and the reaction is highly exothermic and the resulting product is UO 2 . 24 [UO 2 ((N 2 H 3 ) 2-CO) 3 ](NO 3 ) contains carbohydrazide (hydrazine derivative) and vigorously decomposes exothermally at 215 1C with the formation of U 3 O 8 under inert conditions. 25 One may conclude that U(VI) complexes with reactants similar to hydrazine have higher thermal stability, though the reduction of U(VI) is going deeper and may even lead to the formation of UO 2 .…”

“…It is interesting to compare the thermal stability of x UO 3 · y N 2 H 4 · z H 2 O with other complexes of U( vi ) and nitrogen-based reductants. It has been demonstrated 24 that [UO 2 (NH 2 O) 2 (H 2 O) 2 ]·H 2 O loses crystallization water and decomposes at 165 °C, while intramolecular U( vi ) reduction by hydroxilamine occurs at 185 °C. Anhydrous [UO 2 (NH 2 O) 2 ] also decomposes at 185 °C, and the reaction is highly exothermic and the resulting product is UO 2 .…”