Neptunium(IV) fluoride

Neptunium(IV) fluoride or neptunium tetrafluoride is a inorganic compound with the formula NpF4. It is a green salt and is isostructural with UF4.

Synthesis
Neptunium(IV) fluoride can be prepared by reacting neptunium(III) fluoride or neptunium dioxide with a gas mixture of oxygen and hydrogen fluoride at 500 °C:


 * $$\mathrm{4\ NpF_3\ +\ O_2\ +\ 4\ HF\ \longrightarrow \ 4\ NpF_4\ +\ 2\ H_2O}$$

It can also be prepared by treating neptunium dioxide with HF gas:
 * $$\mathrm{NpO_2\ +\ 4\ HF\ \longrightarrow \ NpF_4\ +\ 2\ H_2O}$$