Iodine, elemental reactions with

Chemical ingenuity in using the properties of the elements and their compounds has allowed analyses to be carried out by processes analogous to the generation of hydrides. Osmium tetroxide is very volatile and can be formed easily by oxidation of osmium compounds. Some metals form volatile acetylacetonates (acac), such as iron, zinc, cobalt, chromium, and manganese (Figure 15.4). Iodides can be oxidized easily to iodine (another volatile element in itself), and carbonates or bicarbonates can be examined as COj after reaction with acid. 

Ana.lysls. The available chlorine (av CI2) in hypochlorite solutions or soHds is deterrnined by reaction with aqueous KI, followed by acidification with either acetic or sulfutic acid and titration of the Hberated iodine with standard thiosulfate. The av CI2 in a hypochlorite is a measure of the oxidi2ing capacity expressed in terms of elemental chlorine one hypochlorite ion is equivalent to one CI2 molecule. Thus pure Ca(OCl)2 has an av CI2 of 2 x mol wt... 

The chemical potential diagram for this ternaty system (Figure 3.3) shows that the reaction with the elements would reduce the iodine pressure to a very low value, which is not suitable for CVD, whereas tire compound Ta5Si3, in which the chemical potentials of the two elements are about 40kJgram-atom would be suitable for CVD at about 1300 K. 

Like simple elemental halogens, iodine monochloride reacts with conjugated fluorodienes to yield mostly 1,4-addition products. These bidirectional reactions lead to mixtures of regioisomers, as shown in Table 5 [//]. 

One Au-C bond in bis(thiazol-2-ylidene)gold cations is cleaved in the reaction with elemental iodine to give the corresponding (carbene)AuI complex and a 2-iodo-thiazolium salt, while chlorine and bromine oxidize the gold center to the gold(m) state.267... 

Undoubtedly, the best method for the production of pure anhydrous lanthanide trihalides involves direct reaction of the elements. However, suitable reaction vessels, of molybdenum, tungsten, or tantalum, have to be employed silica containers result in oxohalides (27). Trichlorides have been produced by reacting metal with chlorine (28), methyl chloride (28), or hydrogen chloride (28-31). Of the tribromides, only that of scandium has been prepared by direct reaction with bromine (32). The triiodides have been prepared by reacting the metal with iodine (27, 29, 31, 33-41) or with ammonium iodide (42). 

Arsenic triiodide is prepared by treating elemental arsenic with a solution of iodine in carbon disulfide. Alternatively, it can be precipitated out from a hot solution of arsenic trioxide or arsenic trisulfide in hydrochloric acid on treatment with potassium or sodium iodide. Also, it is made by the reaction of arsenic trichloride with potassium iodide. 

In the work reported here, which was directed toward the attainment of an isotopic enrichment of the trivalent actinide and lanthanide elements, the problem was compounded by the fact that these elements do not readily form appropriate compounds, like iodine in ethyl iodide. They do form some stable organic chelates, and, indeed, it is possible to obtain a Szilard-Chalmers reaction with such compounds. However, their radiation damage resistance does not appear adequate to permit useful production of an isotope like 247Cm, which requires a thermal neutron exposure ap-... 

Diorgano tellurium compounds are easily converted to diorgano tellurium diiodides upon treatment with elemental iodine. The reactions are carried out with solvents such as benzene, chloroform, carbon tetrachloride, and 1,2-dichloroethane. Because iodine is much less reactive than chlorine or bromine, the reactions can be performed at 20 . The diorganyl tellurium diiodides generally precipitate upon mixing the reagents. 

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