Cesium occurrence

These considerations also explain the occurrence of cases of dimorphism involving the sodium chloride and cesium chloride structures. It would be expected that increase in thermal agitation of the ions would smooth out the repulsive forces, that is, would decrease the value of the exponent n. Hence the cesium chloride structure would be expected to be stable in the low temperature region, and the sodium chloride structure in the high-temperature region. This result may be tested by comparison with the data for the ammonium halides, if we assume the ammonium ion to approximate closely to spherical symmetry. The low-temperature form of all three salts, ammonium chloride, bromide and iodide, has the cesium chloride structure, and the high-temperature form the sodium chloride structure. Cesium chloride and bromide are also dimorphous, changing into another form (presumably with the sociium chloride structure) at temperatures of about 500°. 

Two systems based on crown-calixarenes, able to be used in liquid-liquid extraction process were chosen. Both systems use a modifier in the organic phase to avoid the occurrence of a third phase in the TPH (diluent used at the reprocessing plant of la Hague for the PUREX process) and ensure a sufficient cesium extraction. 

The history of atomic emission spectrometry (AES) goes back to Bunsen and Kirchhoff, who reported in 1860 on spectroscopic investigations of the alkali and alkali earth elements with the aid of their spectroscope [1], The elements cesium and rubidium and later on thorium and indium were also discovered on the basis of their atomic emission spectra. From these early beginnings qualitative and quantitative aspects of atomic spectrometry were considered. The occurrence of atomic spectral lines was understood as uniequivocal proof of the presence of these elements in a mixture. Bunsen and Kirchhoff in addition, however, also estimated the amounts of sodium that had to be brought into the flame to give a detectable line emission and therewith gave the basis for quantitative analyses and trace determinations with atomic spectrometry. 

Radium. The radium source used in brachytherapy uses mostly radium sulfate or radium chloride mixed with an inert filler and loaded into cells about 1 cm long and 1 mm in diameter. These cells are made of 0.1- to 0.2- mm-thick gold foil. Radium sources are manufactured as needles or tubes in a variety of lengths and activities. Leakage of radon gas from a radium source represents a significant hazard if the source is broken. The sources are, however, doubly encapsulated to prevent such an occurrence. Cesium-137 has replaced radium, at least in the US. 

Paquette, J., Ford, B. L. The radiation-induced formation of iodoalkanes and the radiolysis of iodomethane. Proc. 2. CSNI Workshop on Iodine Chemistry in Reactor Safety, Toronto, Can., 1988 Report AECL-9923 (1989), p. 48-73 Paquette, J., Sunder, S., Torgerson, D. F., Wren, C. J., Wren, D. J. The chemistry of iodine and cesium under reactor accident conditions. Proc. 3. BNES Conf. Water Chemistry in Nuclear Reactor Systems, Bournemouth 1983, Vol. 1, p. 71—79 Parsly, L. F. Chemical and physical properties of methyl iodide and its occurrence under reactor accident conditions. Report ORNL-NSIC-82 (1971)... 

The reliability of the solubility data for cesium dihydrogenphosphate depends on the analytical method that was used. This matter was discussed by Bykova, et al. (3) and they were careful in their experimental work. Their data agree fairly well with those obtained by extrapolation of solubility isotherms measured by others (4). Therefore, the data of Bykova, et al, (3) as well as their equation for the temperature dependence of the solubility of cesium dihydrogenphosphate are recommended values. The solubility data published by others (5, 6) are rejectee because of analytical uncertainties. The only information that can be considered to be proved Is the occurrence of solid solutions in the CSH2PO4-NH4H2PO4-H2O and CSH2PO4-KH2PO4-H2O systems at 298 K,... 

Ruff andZedner have found similar phase separations for lithium-and potassium-ammonia solutions. Kraus and Johnson have confirmed the occurrence of phase separation for lithium-ammonia solution. Hodgins has performed careful vapor pressure and conductance measurements in cesium-ammonia solutions in the concentration range 0.04 M to 7Af but did not find any evidence for phase separation. Kraus has found from vapor pressure measurements that a liquid-liquid phase separation occurs below — 32.5° C and above a concentration of about 2M 5 mole per cent). Also the curve for vapor pressure as a function of concentration indicates the formation of the solid compound Ca(NHj)g at a temperature of — 32.5° C and concentration larger than 4 Af. 

A study published quite some time ago reviewed the soil-cancer relationship for gastric, esophageal, urinary, breast, bone, and bronchial cancers as well as pleural mesothelioma. In addition to general factors, the study considered trace elements including selenium, cesium, and rubidium potassium and natural radioactivity. Although some correlations between soil constituents and cancer have been observed, the cause and effect relationship between soil characteristics and occurrence of cancer could not be proved definitively. 

---