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The reactions of iodine pentafluoride with typical oxides, salts, and metals are described. They lead to a number of new compounds many of which are of a molecular type. A straightforward method of preparing iodine oxytrifluoride is given and the reactions involved are made clear. Thermal decomposition of this compound gives rise to the new iodyl fluoride, I0,F; this can be reconverted into the oxytrifluoride by heating it with iodine pentafluoride. A study of some of these reactions and the physicochemical properties of iodine pentafluoride is still in progress.IODINE PENTAFLUORIDE was originally prepared by Moissan (Compt. rend., 1902,135,563) who made a cursory and qualitative investigation of its reactions with a large number of metals. Emelkus and Sharpe recently (J., 1949,2206) focused attention on the compound by preparing the polyhalide KIF,, and showing the probable existence of an acid-base system in this solvent similar to that furnished by bromine trifluoride (Woolf and Emelhs, J., 1949, 2865). In the same laboratory, Woolf (J., 1950, 3678) showed that iodine pentafluoride reacts with antimony pentafluoride to give SbIF,,, with sulphur trioxide to give a constant-boiling mixture IF5,1-17S03, and with potassium metaphosphate, persulphate, and iodate to give KP0,,2.31F5, K2S20,,1~021F5, and KI03,0*51F,, respectively.Our interest in the compound arose from a claim by Ruff and Braida (2. anorg. Chem., 1934,42,220 ; Angew. Chem., 1934,47,48) to have obtained iodine oxytrifluoride from iodine pentafluoride in three ways : (a) as a by-product in the preparation of iodine pentafluoride from its elements, provided a little oxygen was present during the reaction, (b) by restricted addition of water to iodine pentafluoride, and (c) by reaction between iodine pentafluoride and iodine pentoxide. The second method did not appear likely to give a unique product or a mixture readily separable, but we gave extended trial to the first method, using, as a source of oxygen, the gas itself and also silica powder mixed with the iodine. I n every case, even when considerable quantities were used, we got iodine pentafluoride which on distillation left a minute, white residue insufficient for identification. The fluorination of iodine pentoxide with fluorine diluted to various extents with nitrogen gave no better results ; but iodine pentoxide dissolved in boiling iodine pentafluoride to a colourless solution which, on cooling to room temperature, deposited white crystals of iodine oxytrifluoride : 1205 + 31F5 + 510F3. This reaction Ruff and Braida believed to be reversible on heating, but this is not the case. It goes smoothly until all the oxide is consumed, the oxy-compound dissolving in the excess of pentafluoride. Actually, on heating the oxytrifluoride at 110" we observed a new reaction leading to the hitherto unrecorded iodyl fluoride, I0,F : 210F3 I/ 10,F + IF,. This is an interesting change because it is reversible. When iodyl fluoride is refluxed with iodine pentafluoride it goes completely into solution, and...

Selenium selenocyanate reacts with diphenyl-and dimethyl-mercury to give the compounds RHgSeCN and RSeCN (R = Ph or Me), and selenium. The new compounds phenyl-and methyl-mercury(I1) selenocyanate have also been prepared by metathesis of mercury(I1) selenocyanate and diphenyl-(or dimethyl-) mercury. Selenium dicyanide cleaves the phenyl-mercury bond to give plienyl selenocyanate and phenylmercury(I1) cyanide. The infrared and Raman spectra of phenyl-and methyl-selenocyanate, and the infrared spectra of the compounds phenylmercury(I1) selenocyanate, phenylmercury(I1) cyanide, phenylmercury(I1) iodide, mercury(I1) selenocyanate, and methylmercury(I1) selenocyanate, have been recorded and assignments made.ALTHOUGH selenium selenocyanate, Se(SeCN),, can be prepared by a variety of routes the chemistry of this compound has received little attention. However it is known that triphenylbismuth reacts with selenium selenocyanate to yield diphenylbismuth selenocyanate, phenyl selenocyanate, and selenium.2

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Potassium selenocyanate reacts with iodine pentafluoride to give selenium dicyanide, Se(CN),, and selenium selenocyanate, Se(SeCN),. The reaction is an unusual example of a mild oxidation in which the selenocyanate ion is first converted into selenocyanogen, (SeCN),, which then disproportionates into the two products. The infrared spectra of the compounds Se(CN),, (SeCN),, and Se(SeCN), are reported and compared with those of related compounds.VERNEUIL~ found that both chlorine and bromine (but not iodine) react with sodium, potassium, or ammonium selenocyanate to give selenium selenocyanate, Se(SeCN),, and Muthmann et al. obtained this product by treating a suspension of potassium selenocyanate in ice-cold water with dinitrogen tetroxide and a little fuming nitric acid. Selenium selenocyanate has also been prepared by reactions between lead selenocyanate and bromine,s between diselenium dibromide and silver ~y a n i d e ,~ by heating sulphenyl selenocyanates,Ssa and by the disproportionation of selenocyanogen, (SeCN),.4