Rhenium dioxide trifluoride

Rhenium dioxide trfluoride is an inorganic compound with the formula ReO2F3. A white diamagnetic solid, it one of the few oxyfluorides of rhenium, another being rhenium trioxide fluoride, ReO3F. The material is of some academic interest as a rare example of an dioxide trifluoride. It can be prepared by the reaction of xenon difluoride and rhenium trioxide chloride:
 * 2 ReO3Cl + 3 XeF2  ->  2 ReO2F3  +  O2  +  Cl2  +  3 Xe

According to X-ray crystallography, the compound can exist in four polymorphs. Two polymorphs adopt chain-like structures featuring octahedral Re centers linked by [bridging bridging fluoride]]s. Two other polymorphs adopt cyclic structures (ReO2F3)3 and (ReO2F3)4, again featuring octahedral Re centers and bridging fluorides. Like related oxyfluorides, these coordination oligomers break up in the presence of Lewis bases. Adducts of the formula ReO2F3L where L = acetonitrile have been crystallized.