Polyvalent iodine species

Six structural types of polyvalent iodine species are commonly encountered, as shown below ... 

Iodine can form organic compounds with oxidation states of +3 and 4-5. The most common stmctural types of organic polyvalent iodine species are represented by structures 1—3, shovm in Figure 1. Structure 1, the iodo-nium ion, formally does not belong to hypervalent species since it has only eight valence electrons on the iodine atom however, in the modem Hterature iodonium salts are commonly treated as the 10-electron hypervalent... 

Iodine differs in many aspects from the other halogens. Because of the large atomic size and the relatively low ionization energy, it can easily form stable polycoordinate, multivalent compounds. Interest in polyvalent organic iodine compounds arises from several factors (a) the similarity of the chemical properties and reactivity of I(III) species to those of Hg(+2), Tl(+3), and Pb(+4), but without the toxic and environmental problems of these heavy metal congeners ... 

The only known alternative procedure for the preparation of alkynyl(phenyl)iodonium arylsulfonates, the latest member of the family of polyvalent Iodine compounds, involves the reaction of [hydroxy(tosyloxy)iodo]benzene. PhlOH-OTs, with terminal alkynes as first reported by Koser and elaborated by us. This procedure has a number of shortcomings. Formation of the desired alkynyliodonium salt is usually accompanied by a related vinyl species, R(TsO)C=CHIPh-OTs, that both decreases the yields and causes purification problems. Furthermore, when the alkyl substituent of the starting alkyne is small, such as CH3, n-Pr, n-Bu, etc., this procedure gives either no product or low yields at best. 

In the case when defective fuel rods are present in the reactor core, the BWR reactor water contains the other fission products and the activation products released from the fuel in concentrations well below those of fission product iodine. This applies as well for fission product cesium, which is retained on the ion exchangers of the reactor water cleanup system with a decontamination factor of about 100. As far as it is known, cesium in the reactor water is present as the Cs ion, whereas large proportions of most of the polyvalent fission products and of the actinides are attached to the corrosion product particles suspended in the water as yet, there is no detailed knowledge on the chemical state of these elements (i. e., adsorbed to the surfaces or incorporated into the Fe203 lattice). It was reported that the strontium isotopes as well as Np appear in the reactor water in the dissolved cationic state, while Tc was found in the reactor water as a dissolved anionic species, most likely Tc04 (Lin and Holloway, 1972). According to James (1988), discrete fuel particles were not detected in the BWR reactor water. 

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