Rhenium trioxide fluoride

Rhenium trioxide fluoride is an inorganic compound with the formula ReO3F. It is a white, sublimable, diamagnetic solid, although impure samples appear colored. It one of the few oxyfluorides of rhenium, the other major one being rhenium dioxide trifluoride ReO2F3. The material has no applications, but it is of some academic interest as a rare example of a trioxide fluoride.

Synthesis and reactions
Rhenium trioxide fluoride can be prepared by fluorination of rhenium trioxide:
 * 2 ReO3 + F2 ->  2ReO3F

With Lewis bases (L) the compound forms adducts with the formula ReO3FL2, e.g., L = diethyl ether and acetonitrile.

Structure and related compounds
According to X-ray crystallography, the compound adopts a helical chain structure featuring octahedral Re centers linked by two fluoride and two oxide bridging ligands. In contrast with ReO3F, TcO3F and MnO3F crystallize with simpler structures. The Mn compound crystallizes as a tetrahedral monomer. The technetium compound TcO3F crystallizes as dimers with fluoride bridges. Also contrasting with the structure of rhenium trioxide fluoride is that of rhenium trioxide chloride, which is a monomer.