Crystal structures of high-valent transition-metal chalcogenide fluorides

The structures of high-valent transition-metal chalcogenide fluorides are of interest since it is not clear whether they will be related to those of their oxide-fluoride analogues or to those of the transition-metal chalcogenide chlorides and bromides. This will depend on the extent to which substitution of fluorine for chlorine or bromine or sulphur, or selenium for oxygen has the more significant effect.The first single-crystal structure on a compound of this class, WSF₄, shows that it consists of octahedrally coordinated tungsten atoms linked by cis-bridged fluorine atoms into polymeric chains. This, together with work on the structure of ReSF₄, suggests that the tendency is to follow oxide-fluoride and fluoride structures.