Cesium content

Cesium hydrogen carbonate [15519-28-5], CsHCO, mol wt 193.92, theoretical cesium content 68.54%, is a colorless, slightly hygroscopic, crystalline sohd having a specific gravity of ca 1400 kg/m, which decomposes at 175°C. Ithas a solubUity of 2.1 kg/L. 

Cesium Halides. Cesium bromide, [7787-69-1], CsBr, mol wt 212.82, theoretical cesium content 62.45%, is a colorless crystalline soUd, having a melting point of 636°C, a specific gravity of 4433 kg/m, and a solubUity of 1.23 kg/L of water at 25°C. It is usuaUy prepared by neutrali2ing the carbonate or hydroxide with HBr, but it is also the primary product of the Dow process (25) for poUucite processing. 

Cesium perchlorate [13454-84-7], CsClO, mol wt 232.35 and theoretical cesium content hi.25/q, is a crystalline powder that decomposes at 250°C Cesium fluoride [13400-13-0], CsF, mol wt 151.90, theoretical cesium content 87.49%, has a melting point of 682—703°C and a boiling point of 1253°C. Cesium fluoride is an extremely hygroscopic, colorless, crystalline soUd it has a solubUity of 3.665 kg/L of water at 18°C. Cesium fluoride is made by exactly neutrali2ing cesium hydroxide with hydrofluoric acid and evaporating the resultant solution to dryness at 400°C. Excess HE results in a bifluoride salt that does not decompose at 400°C, and carbonate in the starting material gives an alkaline product. 

Cesium hydroxide monohydrate [35103-79-8] CsOH H2O, mol wt 167.93, theoretical cesium content 79.14 wt %, is a colorless, hygroscopic, crystalline powder, having a melting point of 205—208°C and a specific gravity of 3500 kg/m. It is highly soluble, 8.6 kg/L of water at 15°C similar to the anhydrous hydroxide, it is an extremely strong base. 

Cesium Oxides. Cesium forms a series of oxides, including cesium monoxide [20281-00-9] mol wt 281.81, theoretical cesium content... 

Cesium Permanganate. Cesium permanganate [13456-28-5], CsMnO, mol wt 251.84, theoretical cesium content 52.77 wt %, has a specific... 

Cesium Sulfates. Cesium sulfate [10294-54-9], Qs O, mol wt 361.87, theoretical cesium content 73.46 wt %, forms colorless, rhombic, or... 

Other Cesium Compounds. Cesium acetate [3396-11-0], CsOOCCH, mol wt 191.95, theoretical cesium content 69.24 wt % cesium trifluoroacetate, CF COOCs, mol wt 245.93, theoretical cesium content 54.04 wt % cesium—precious metal compounds such as cesium dicarbonyltetrachloromthenium, [22594-81-6] Cs2RuCl4(CO)2, mol wt 564.71, mthenium content of 17.9 wt %, a yellow crystalline powder and cesium tetrachlorogold [13682-60-5], CsAuCl, mol wt 471.7, gold content of 41.8 wt % a yellow powder are all known. 

The agreement between these two tests indicated no significant change in leach rate with time on this short time scale, for the particular elements studied ( i.e.j barium, strontium, cerium, and rare earths). It was not possible to determine the cesium content in these granules because, for economy reasons, cesium was not included in the calcine production. The results of these measurements are given in Table III. Significant differences in the leach rates of the alkaline earths (barium, strontium) the RE (europium), and cerium are observable. 

The chemical yield of each element was usually about 70%. The rubidium content of the 12 County Durham coals was 6-30 ppm, and the cesium content in 10 of the coals was 0.8-3.7 ppm. Reproducibility of results was very good for cesium the relative standard deviation of the mean result was usually less than 5%. Rubidium results were slightly less reproducible, the largest relative standard deviation being 22%. 

Rubidium typically exists in the human body at the level of only 1/1,000 of 1 percent, and cesium content is even lower. Rubidium and cesium are both absorbed from soil by plants and are, therefore, present in small quantities in vegetables and up the food chain to meat products and humans. Rubidium is known to stimulate mammalian metabolism, probably because of its physical and chemical similarity to potassium, which plays a crucial role in electrical pulse transmission along nerve fibers protein synthesis acid-base balance and formation of collagen, elastin, and muscle. Its likeness to potassium may be the reason rubidium enhances growth in some plants. For particular insects, however, the introduction in the laboratory of rubidium to the bloodstream has been shown to drastically reduce fluid secretion and to change the electric potential across cell membranes. Excess rubidium is almost never encountered, however, in nature. 

Brewer thought this very low cancer incidence among the Hopi was due to the high cesium content in their diet, attributable to the high cesium content of the... 

MgO was found to be the most active catalyst for the hydrogen transfer reaction, then potassium impregnated gamma alumina (y-ALO -K), y-Al203, and CsNaX zeolites. With the zeolites MPVO aetivity decreased with decreasing cesium content. The opposite trend was observed for the acid-catalyzed dehydra-... 

Additions of stable cesium to the environment as a result of human activities are few in number, and are also very improbable due to the low technical importance of cesium and the very low cesium content of fuels. Consequently, contamination of the atmosphere, waste waters or sewage sludges by stable cesium isotopes are largely unknown. The situation differs, however, in the case of radioactive isotopes of cesium (see Section 1.5.8), as nuclear plants - and especially those in which uranium is regained - may in exceptional circumstances cause massive pollution of the air, soil and water. 

The cesium contents of soils vary analogously with their potassium contents (Oughton and Day, 1993). Forest and moor soils have lower potassium contents than farmed soils, where the fertilizers used substitute for potassium losses following uptake by the vegetation. The typical cesium content of pastures is 1-2 mgkg (Oughton and Day, 1993), while the Cs contents of soil may range from 0.5 to 20 mg kg (Shaw and Bell, 1991). 

To date, no sign of essentiality for plants, animals, and humans have been reported for cesium neither has any biomagnification by fauna been described, and soil concentrations of cesium are always much higher than that of both plants and animals. Cesium bioconcentration has not been observed in any specialized parts of plants, except for the skin of the hats of certain types of mushrooms, wherein cesium (detected as radiocesium) accumulates to high levels. In this situation it is thought that the cesium is enriched in the color pigments of the hat skin (Kalac, 2001). The potassium content of the mushroom was also found to relate inversely to the cesium content in other words, the higher the potassium content, the lower the cesium content (Marin et al., 1997). 

Fifiy to almost one hundred percent of the cesium content of the food are absorbed by... 

Radiocesium is an excellent indicator for the behavior of inactive cesium in the biosphere because its radiation can be detected rather quickly, its passage through the compartments of biosystems can be studied much more easily than by direct estimation of the inactive cesium content. Thus, the behavior of radiocesium in ecosystems supplies much information relating to cesium transport in the atmosphere, soil, plants, and animals. 

Oceanic water has a cesium content of about 0.5lpg and a strontium content of about 8000 pgU. Uptake in a marine organism is most likely to be in proportion to the abundance of the radioactive and the nonradioactive isotopes of the actual element. This can be illustrated by the following example. The sunken nuclear submarine Komsomolets contained an estimated (lowest) amount of 1.55 PBq °Sr (about 300 g) and 2.03 PBq... 

The reactions of the above di- and triphenylalkanes with cesium alloys caused us to wonder whether benzene would give a similar reaction. The literature revealed that Hackspill (< 6) had found that benzene reacted with cesium at 28°C to give a black solid of cesium content near that of CsHjCs so that the compound was initially supposed to be phenylce-sium however, since treatment of the black precipitate with water yielded hydrogen and biphenyl, the assignment of structure was later... 

On April 11, 1860, R. Bunsen wrote to G. Roskoe (his collaborator in a study in photochemistry) about his investigation of the new alkali metal. On May 10 he reported the discovery of cesium to the Berlin Academy of Sciences. Six months later Bunsen already had 50 g of almost pure cesium chloroplatinate. To obtain such an amount of the product, it was required to process nearly 300 tons of mineral water about one kilogram of lithium chloride was isolated as a side product. These figures show how small was the cesium content in mineral spring waters. 

Figure 3.21 Silicon substrate work-function variation as a function of Cesium content introduced through implantation from 1 keV Cs primary ion impact at 60°. In the inset is the response of the Si and Si" secondary ion intensities. The work-function value was adjusted through the deposition of Cesium onto and into the Silicon substrate (Cesium, like all alkali metals, reduces the work-function value of all metals and semiconductors). Reproduced with permission from van der Heide (2004) Copyright 2004 Elsevier.

An example of the reduction in the work-function imparted by the presence of Cesium on and within a Silicon surface (that induced by the fraction implanted in Silicon on sputtering with a Cs primary ion beam) is shown in Figure 3.21. The inset of Figure 3.21 shows the resulting variations in the Si and Si secondary ion intensities from the aforementioned Silicon substrate as a function of concentration of Cesium implanted into the Silicon substrate. As can be seen, the positive secondary ions are quenched in an exponential-like manner with increasing Cesium content, whereas the positive secondary ions are enhanced, also in an exponential-like manner. These trends can be described by the relations ... 

Indeed, the probability of Cesium to form Cs secondary ions is, in the majority of cases, independent of the position of the Fermi edge, which itself is dne to the very low ionization potential of Cesium, i.e. this places the Cesium ionization level well above the Fermi edge of most surfaces. This insensitivity to the position of the Fermi edge can thus explain the trends in Cs secondary ions from most Cs sputtered metal and semiconductor surfaces and why these are seen to increase over the transient region, with the increase simply reflecting the increased Cesium content implanted into the respective snbstrate. 

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