Neptunyl fluorideNeptunyl fluoride is an inorganic compound of neptunium, oxygen, and fluorine with the chemical formula.SynthesisNeptunyl fluoride can be obtained by the reaction of the hydrated trioxide with gaseous HF and by direct fluorination of at 350 °C or at 225 °C.Physical propertiesThe compound forms a pink solid of hexagonal crystal system, spatial group R3''m''. Soluble in water, insoluble in common organic solvents.