Radon oxide

M. A., Coprecipitation of Radon Oxide with Cesium Fluoroxenate, Radiokhim. 27 511-514 (1985). 

The chemistry of radon (II) was outlined by Stein in 1983 (14). Since then, evidence for radon in a higher oxidation state (RnF4 or RnF6) and a radon oxide (Rn03) has been claimed and disputed, and the ions, [HRn03]+, [HRnOJ-, and [RnOjFJ have been reported. 

The physico-chemical properties of radon and its decay products are presented in a series of reports primarily focusing on the decay products. However, Stein (1987) presents a review of his pioneering studies of radon chemistry and the reactions of radon with strong oxidizing agents. Although radon is not chemically active in indoor air, it is interesting to note that radon is not an "inert gas. 

Since the discovery of the first noble gas compound, Xe PtF (Bartlett, 1962), a number of compounds of krypton, xenon, and radon have been prepared. Xenon has been shown to have a very rich chemistry, encompassing simple fluorides, XeF2> XeF, and XeF oxides, XeO and XeO oxyf luorides, XeOF2> XeOF, and Xe02 2 perxenates perchlorates fluorosulfates and many adducts with Lewis acids and bases (Bartlett and Sladky, 1973). Krypton compounds are less stable than xenon compounds, hence only about a dozen have been prepared KrF and derivatives of KrF2> such as KrF+SbF, KrF+VF, and KrF+Ta2F11. The chemistry of radon has been studied by radioactive tracer methods, since there are no stable isotopes of this element, and it has been deduced that radon also forms a difluoride and several complex salts. In this paper, some of the methods of preparation and properties of radon compounds are described. For further information concerning the chemistry, the reader is referred to a recent review (Stein, 1983). 

Radon reacts spontaneously at room temperature with many solid compounds that contain oxidizing cations, such as BrF2, IF, 02, and N2F (Stein, 1972, 1973, 1974 Stein and Hohorst, 1982). Xenon also reacts with a few compounds of this type which have very high oxidation potentials (Stein, 1973, 1974). The xenon products have been analyzed by Raman and mass spectrometric methods and shown to... 

This behavior provides evidence that in each of the compounds, radon is in the +2 oxidation state When higher-valent xenon compounds, such as XeF and XeF, are hydrolyzed, water-soluble xenon species (XeO and XeO ) are produced (Malm and Appelman, 1969). We have observed no radon species corresponding to these xenon species in hydrolysis experiments. 

Russian scientists (Avrorin et al., 1981, 1985) have reported that reactions of complex mixtures of radon, xenon, metal fluorides, bromine pentafluoride, and fluorine yield a higher fluoride of radon which hydrolyzes to form RnO. However, efforts to confirm these findings have been unsuccessful. In similar experiments which have been carried out at Argonne National Laboratory (Stein, 1984), it has been found that radon in the hydrolysate is merely trapped in undissolved solids centrifugation removes the radon from the liquid phase completely. This is in marked contrast to the behavior of a solution of XeO, which can be filtered or centrifuged without loss of the xenon compound. Hence there is no reliable evidence at present for the existence of a higher oxidation state of radon or for radon compounds or ions in aqueous solutions. Earlier reports of the preparation of oxidized radon species in aqueous solutions (Haseltine and Moser, 1967 Haseltine, 1967) have also been shown to be erroneous (Flohr and Appelman, 1968 Gusev and Kirin, 1971). 

Stable solutions of radon difluoride can be prepared in nonaqueous solvents, such as halogen fluorides and hydrogen fluoride (Stein, 1969, 1970). Radon reacts spontaneously at 25°C or at lower temperatures with each of the halogen fluorides except IF3. It also reacts with mixed solvent-oxidant pairs, such as HF-BrF, HF-BrF, and IF -BrF, and solutions of NiF in HF. 

We have found that similar behavior occurs when the column is packed with other salts of Group I elements, such as NaSbF Na AlF, or NiF, or with Nafion ion-exchange resins (H or K forms). In batch equilibration experiments, using 1 g amounts of solids stirred with 5-15 ml volumes of solutions, we have found that the radon ions can also be collected on the compounds CsBrF, Ca(BrF )2, and Ba(BrF )2. Thus it is apparent that, in its oxidized state, radon can displace H, Na, K, Cs, Caz, and Baz ions from a number of solid materials. 

Stein, L., Oxidized Radon in Halogen Fluoride Solutions, J. Am. Chem. Soc. 91 5396 (1969). 

Stein, L. and Hohorst, F. A., Collection of Radon with Solid Oxidizing Reagents, Environ Sci. Technol. 16 419-422 (1982). 

Figure 4a shows the results for CN levels at 70 cm 3 and below. As pointed out earlier (Holub, 1984), there are no attached radon daughters because the attachment rate is negligible compared to 218Po half life. There is no observable growth and the clusters are very close to the oxide of 218Po. All sets agree reasonably well. Error bars are from repeated measurements. 

Welders are typically exposed to a complex mixture of dust and fume of metallic oxides, as well as irritant gases, and are subject to mixed-dust pneumoconiosis with possible loss of pulmonary function this should not be confused with benign pneumoconiosis caused by iron oxide. Although an increased incidence of lung cancer has been observed among hematite miners exposed to iron oxide, presumably owing to concomitant radon gas exposure, there is no evidence that iron oxide alone is carcinogenic to man or animals. ... 

Table 15.1 summarizes the major species of concern for indoor air pollution and some of their sources (Su, 1996). We focus in this chapter primarily on those species common to indoor and outdoor air environments, including oxides of nitrogen, volatile organic compounds (VOC), CO, ozone, the OH radical, S02, and particles. In addition, a brief discussion of radon is included since this has been one of the major foci of concern in the past with respect to indoor air pollution. 

Fig. 4. Optical micrographs of (A) hot-pressed (at ANSTO) and (B) ICCM-produced (at SIA Radon) Synroc-C, loaded with 20 wt% HLW oxides. Scale bars 500 p.m (Sobolev et al. 19974).

Table 6.18 contains the small amount of data for the + 6 and + 7 states of Xe. All four species are extremely unstable and must be handled very carefully. It is probable that radon has a similar chemistry, and there is a possibility that some higher oxidation states of krypton exist. 

RADIUM. [CAS 7440-14-41, Chemical element symbol Ra, at. no. 88, at. wt. 226.025, periodic table group 2 (alkaline earths), mp 700VC, bp 1,140°C, density 5 g/cm3 (20°C). Radium metal is white, rapidly oxidized in air, decomposes H O, and evolves heat continuously at the rate of approximately 0.132 calorie per hour per mg when the decomposition products are retained, and the temperature of radium salts remains about 1,5°C above the surrounding environment. Radium is formed by radioactive transformation of uranium, about 3 million parts of uranium being accompanied in nature by 1 part radium. Radium spontaneously generates radon gas at approximately the rate of 100 mmJ per day per gram of radium, at standard conditions, Radium usually is handled as the chloride or bromide, either as solid or in solution. The radioactivity of the material... 

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