Formula NbF4 Melting point 350 °C | Molar mass 168.9 g/mol Appearance black solid | |
Niobium(IV) fluoride is a chemical compound with the formula NbF4; it is a nonvolatile black solid. It absorbs vapor strongly. It turns into NbO2F in moist air. NbF4 reacts with water to form a brown solution and a brown precipitate whose components are unknown. It is stable between 275 °C and 325 °C when heated in a vacuum. However, it disproportionates at 350 °C rapidly to form niobium(V) fluoride and niobium(III) fluoride:
Structure
Niobium(IV) fluoride adopts a crystal structure analogous to that of tin(IV) fluoride, in which each niobium atom is surrounded by six fluorine atoms forming an octahedron. Of the six fluorine atoms surrounding a single niobium atom, four are bridging to adjacent octahedra, leading to a structure of octahedra connected in layers.