Uranium pentafluoride an inorganic chemical consisting of uranium and fluorine. The compound exists both as individual UF5 molecular entities and with extended order in several crystal-lattice forms. The monomer, formed by photolysis of uranium hexafluoride, has a square pyramidal geometry. The α form is a linear coordination polymer consisting of chains in which one of the five fluoride atoms forms a bridge to the next uranium atom. Uranium pentafluoride can be synthesized in the α form by reducing uranium hexafluoride with sulfur dioxide at 160 °C. The β form, which gradually converts to the α form at 180 °C, has a square antiprismatic lattice structure.