Unconventional Pathways to Carbide Phase Synthesis via Thermal Decomposition of UI4(1,4-dioxane)2.

UI4(1,4-dioxane)2 was subjected to laser-based heating─a method that enables localized, fast heating (T > 2000 °C) and rapid cooling under controlled conditions (scan rate, power, atmosphere, etc.)─to understand its thermal decomposition. A predictive computational thermodynamic technique estimated the decomposition temperature of UI4(1,4-dioxane)2 to uranium (U) metal to be 2236 °C, a temperature achievable under laser irradiation. Dictated by the presence of reactive, gaseous byproducts, the thermal decomposition of UI4(1,4-dioxane)2 under furnace conditions up to 600 °C revealed the formation of UO2, UIx, and U(C1-xOx)y, while under laser irradiation, UI4(1,4-dioxane)2 decomposed to UO2, U(C1-xOx)y, UC2-zOz, and UC. Despite the fast dynamics associated with laser irradiation, the central uranium atom reacted with the thermal decomposition products of the ligand (1,4-dioxane = C4H8O2) instead of producing pure U metal. The results highlight the potential to co-develop uranium precursors with specific irradiation procedures to advance nuclear materials research by finding new pathways to produce uranium carbide.