Platinum tetrafluoride, structure

Attempts to confirm the existence of platinum difluoride have been unsuccessful. Platinum tetrafluoride has been shown to be diamagnetic when pure. Although it is not isomorphous with any known tetrafluoride it is apparently related structurally to uranium tetrachloride. The quinque-positive oxidation state of platinum has been established in the simple fluoride, the salts potassium hexafluoroplatinate(v) and dioxygenyl hexa-fluoroplatinate(v), and in the adducts ClFj.PtFj and IFj.PtFj. Platinum hexafluoride has been briefly investigated. 

F (I) ion donor as selenium tetrafluoride and it is probable that in the platinum tetrafluoride-bromine trifluoride adduct the association is by bifluorine bridging, as represented in (I) or by monofluorine bridging to yield a polymeric structure. 

Although the number of tetrafluorides reported is as large as the number of di- and trifluorides (see Table III), this group of compounds is the least well characterized structurally of the transition metal fluorides. The synthesis of most of the expected tetrafluorides has been reported, with examples from titanium to manganese in the first, from zirconium to palladium (except for technetium) in the second, and from hafnium to platinum (except for tantalum) in the third series. Many of them have been little studied and, in general, they have not proved amenable to crystallographic structural analysis. 

Although a number of complex fluorides of quinquevalent iridium, (e.g. KIrF,) are known, previous attempts to establish the simple fluoride have failed. The absence of a pentafluoride of iridium has become increasingly anomalous as the pentafluorides of the neighbouring elements, rhenium, osmium, and platinum have been prepared. Previous work - indicated that reactions which might have yielded the pentafluoride gave the tetrafluoride instead. The physical properties of this tetrafluoride. (m.p. 106—107 b.p. > 300 ), however, resembled those of a pentafluoride or oxide tetrafluoride. This indicated that iridium tetrafluoride differed structurally from its neighbouring tetrafluorides. 

The tetrafluorides were also, however, of considerable interest for their structural features. Octahedral coordination was already the established platinum-metal atom... 

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