Niobium fluoride is a chemical compound with the formula

Formula

In mathematics, a formula is an entity constructed using the symbols and formation rules of a given logical language....

 NbF₄; it is a nonvolatile black solid

Solid

Solid is one of the three classical states of matter . It is characterized by structural rigidity and resistance to changes of shape or volume. Unlike a liquid, a solid object does not flow to take on the shape of its container, nor does it expand to fill the entire volume available to it like a...

. It absorbs vapor strongly. It turns into NbO₂F in moist air. NbF₄ reacts with water strongly to form brown solution and brown precipitate whose components are unknown. It is stable between 275℃ and 325℃ when heating NbF₄ in vacuum. However, it takes disproportionating reaction over 350℃ rapidly to form niobium(V) fluoride

Niobium(V) fluoride

Niobium fluoride, also known as niobium pentafluoride, is a colorless crystalline solid often used as a starting material in niobium chemistry.-Preparation:...

 and niobium(III) fluoride:
(at 350℃)