Platinum pentafluoride

Xe+[PtFe] formulation is also given by the similarity of the spectra with those of potassium and dioxygenyl hexafluoroplatinates(V). The data are compared in Table 5. That the material containing more platinum than XePtFa contains platinum pentafluoride, arising by the reaction... 

The reaction of xenon with platinum hexafluoride yields at least two distinct quinquevalent platinum products, XePtF, and Xe(PtFj)j. A third compound XePtjFij which is diamagnetic, is produced by heating the former. During continuing investigations of the reaction between xenon, fluorine, and platinum pentafluoride, at least two different compounds have been detected. The better characterized compound is produced when 1 1 molar ratios of xenon and platinum pentafluoride are employed in admixture with 80 p.s.i. 

Platinum Pentafluoride.—This is best prepared by the medium-temperature fluorination of platinum dichloride.i It is a deep red solid which melts at 80 to a viscous red liquid. The ready disproportionation, 2PtFg— PtFg -f- PtF, prevents purification by distillation. Reliable boiling-point determination is not possible and our earlier value must be rejected, since that observed was of tetrafluoride dissolved in pentafluoride. 

The 1 1 chlorine trifluoride-platinum pentafluoride adduct, m. p. I7l , and the 1 1 iodine pentafluoride adduct, m. p. 140° resemble, in their physical properties, the selenium tetrafluoride adducts of osmium pentafluoride (SeF4,OsFg, m. p. 158°) and iridium pentafluoride (SeF. IrFg, m. p. 133°). They are probably bifluorine-bridged monomers ... 

Bromine trifluoride under reflux, dissolved the tetrafluoride to give a deep red solution. The red-brown solid which remained after vacuum distillation of the bromine trifluoride was the 2 1 bromine trifluoride-platinum tetrafluoride adduct [Found F, 35-1 Pt, 36-7. Calc, for (BrFj)2PtF4 F, 34-9 Pt, 34-9%]. The diamagnetic solid melted with some decomposition at 136°. Its X-ray powder pattern was complex and no attempt was made to index it. Iodine pentafluoride neither dissolved nor reacted with the tetrafluoride even on prolonged refluxing at 100°. Chlorine trifluoride, passed over the tetrafluoride at 300°, converted it into a yellow solid, m. p. 170°, of which the X-ray powder pattern was identical with that of the chlorine trifluoride-platinum pentafluoride adduct. ... 

Iodine pentafluoride dissolved platinum pentafluoride, under reflux, to yield a deep red solution. When the excess of solvent was removed, under vacuum at 23°, a pale orange residue remained, which X-ray photography showed to be the 1 1 iodine p>entailuoride-platinum pentafluoride adduct. ... 

Properties of the iodine pentafluoride-platinum pentafluoride adduct. The solid, m. p. 140°, begins to decompose at 180° this is complete at 300° and the residue is platinum tetrafluoride. The adduct is paramagnetic, p = 0-65 B.M. (23°). The X-ray powder pattern was complex and no attempt was made to index it. Water reacted vigorously with it to give a solution containing the hexafluoroplatinate(iv) ion. Reaction with most organic solvents was exothermic and complex, but carbon tetrachloride neither reacted with nor dissolved it. 

The Preparation of Hexafluoroplatinates(v).—The 1 1 chlorine trifluoride-platinum pentafluoride adduct and the salt, potassium hexafluoroplatinate(v), were prepared in quantity only from dioxygenyl hexafluoroplatinate as described in Part II. ... 

Properties of the 1 1 Chlorine Trifluoride—Platinum Pentafluoride Adduct.—The chlorine trifluoride-platinum pentafluoride adduct, m. p. 170—171°, sublimes in a good vacuum at 100°. It is paramagnetic and X-ray powder photographs show it has a low crystal symmetry. It reacts vigorously with water to liberate pungent gases and give a pale yellow solution. Spectroscopic examination of this solution proved the presence of the hexafluoroplatinate(iv) ion with absorption peaJcs at 275 and 315 mp and the absence of the hexachloroplatinate(iv) ion which has a peak at 263 mp. 

Sulfur atoms extraneous to the heteropentalene system in (4 X = S) can be oxidized by MCPBA to SO and SO2 groups in 64-70% yields <85JCS(P2)833>. Arsenic pentafluoride coordinates to the thiadiazole ring of (59 R = Cl) as shown in (15) (x-ray analysis) <86ZN(B)162>, whereas (rj -ethene)bis(triphenyl-phosphane)platinum(0) inserts into the thiadiazole ring to give a new six-membered metallocycle <86CB366>. 

Niobium Pentafluoride, NbFs, is the only known compound of niobium and fluorine, and even this cannot be obtained in the free state by a wet method because of the extreme readiness with which it hydrolyses. Niobium pentoxide dissolves readily in hydrofluoric acid, but evaporation of the solution leaves a residue of the unchanged oxide. Niobium pentafluoride has been prepared synthetically 1 by passing dry fluorine over the gently heated metal contained in a boat in a platinum tube. The product is freed from platinum tetrafluoride, a little of which is formed at the same time, by distillation in vacuo at 100° to 110° . An alternative method consists in treating niobium pentachloride with anhydrous hydrogen fluoride in a freezing mixture and purifying by redistillation.3... 

Niobium pentafluoride forms colourless, highly refractive prisms density 8 2932 at 18° C. It melts at 75 5° C.f and boils at 217° to 220° C. under a pressure of 760 mm. of mercury. It is extremely hygroscopic and deliquesces rapidly in air. It is reduced by hydrogen at 286° C. in contact with platinum to an unstable lower blue fluoride. Excess of concentrated alkali hydroxide or alkali carbonate solutions attack it with formation of the alkali niobate. It dissolves in toluene, paraffin, carbon bisulphide, and other organic solvents. 

Tantalum Pentafluoride, TaFs, is the only known fluoride of tantalum, and has been successfully isolated by methods that avoid hydrolysis (1) Tantalum and fluorine are brought into reaction exactly as in the preparation of niobium pentafluoride.1 (2) Tantalum penta-chloride is treated in the cold with dry hydrofluoric add the hydrochloric acid liberated and excess of hydrofluoric add are evaporated oft, and the resulting tantalum pentafluoride is purified by redistillation in a platinum crucible between 300° and 400° C.2 (3) The double barium tantalum fluoride, 3BaF2.2TaF5, is very strongly heated in a platinum tube, one end of which is kept cold. ... 

Arsenic Pentafluoride, AsFs, may be prepared by the interaction of arsenic and fluorine in a platinum vessel,2 or by the action of bromine and antimony pentafluoride on arsenic trifluoride.3 The reagents should be dry, and if the reaction in the second case is carried out in a glass vessel, the apparatus should be in one piece and well dried. The bromine is added to the mixture of fluorides at - 20° C. and, after cooling in liquid air, the arsenic pentafluoride is obtained by heating on a water-bath at 55° C., the gas passing through a reflux condenser to a receiver surrounded by liquid air. The product contains bromine, which is removed by passing the gas over molten sulphur. 

In general, high reactivity of compounds is associated with high sensitivity. Thermally unstable fluorides may still be prepared under fluorine pressure, if their formation takes place already at moderate temperatures. Hexafluorides of the platinum metals are very strong oxidizers and volatile, but also thermally quite unstable, in particular those that are most reactive. Nevertheless, RuF6 and RhF6 were obtained via pressure fluorination of their respective pentafluorides [92] ... 

SAFETY PROFILE Handle carefully. It may be a sensitizer but not to the same extent as platinum. Most rhodium compounds have only moderate toxicity by ingestion. Flammable when exposed to heat or flame. Violent reaction with chlorine, bromine pentafluoride, bromine trifluoride, and OF2. A catalytic metal. 

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