Cesium ratio

Cesium is very scarce in the Earth s cmst, with an average cmstal content of about 0.65 parts per million, or 6.5x10 %. In cmstal rocks the potassium cesium ratio is 2700 1 (Fleischer, 1954), and in sea water it is 770000 1 (Wessling, 1967). 

Seawater has a potassium cesium ratio of 1 770000, and an absolute concentration of about 0.5 parts per billion (Smales and Salmon, 1955). 

FIGURE 4. Course, with time, of the cesium ratio (Cs) C-DNAJ. ... 

Xenates and Perxenates. Alkali metal xenates of composition MHXe04-1.5H20, where M is sodium, potassium, mbidium, or cesium, have been prepared by free2e-dryiQg mixtures of xenon trioxide and the corresponding metal hydroxides ia 1 1 molar ratios. The xenates are unstable, explosive solids. 

Isomerization of fluoroolefins by a shift of a double bond is catalyzed by halide 10ns [7] The presence of crown ether makes this reaction more efficient [74] Prolonged reaction time favors the rearranged product with an internal double bond (equations 3-5) Isomerization of perfluoro-l-pentene with cesium fluoride yields perfluoro-2-pentenes in a Z ratio of 1 6 [75] Antimony pentafluoride also causes isomenzation of olefins leading to more substituted products [76]... 

The first column of the periodic table, Group 1, contains elements that are soft, shiny solids. These alkali metals include lithium, sodium, potassium, mbidium, and cesium. At the other end of the table, fluorine, chlorine, bromine, iodine, and astatine appear in the next-to-last column. These are the halogens, or Group 17 elements. These four elements exist as diatomic molecules, so their formulas have the form X2 A sample of chlorine appears in Figure EV. Each alkali metal combines with any of the halogens in a 1 1 ratio to form a white crystalline solid. The general formula of these compounds s, AX, where A represents the alkali metal and X represents the halogen A X = N a C 1, LiBr, CsBr, KI, etc.). 

An iron phosphate catalyst with a P/Fe atomic ratio of 1.2 used in this study was prepared according to the procedures described in the previous studies [6-8]. On the other hand, a V-P oxide catalyst with a P/V atomic ratio of 1.06 and pumice supported 12-molybdophosphoric acid (H3PM012O40) and its cesium salt (CS2HPM012O40) catalysts were the same as used in a previous study [9]. Pumice supported W03-based mixed oxide catalysts were the same as used in a previous study [10]. 

Sulphines may react as dienophiles with 1,3-dienes with the formation of cyclic sulphoxides. Unstable 2,2-dichloro-5,6-dihydro-2ff-thiin-l-oxide 191 was formed in an exothermic reaction between 173aandcyclopentadieneat — 40 (equation 101). The simplest, parent sulphine, CH2 = S = O, prepared in situ by treatment of a-trimethylsilylmethanesulphinyl chloride with cesium fluoride, reacts with cyclopentadiene to give bicyclic, unsaturated sulphoxide 192 as a mixture of two diastereoisomers in a 9 1 ratio (equation 102). On the other hand, a,j8-unsaturated sulphine 193 (generated by thermolysis of 2-benzylidene-l-thiotetralone dimer S-oxide) in boiling toluene behaves as a 1,3-diene and was trapped by norborene forming sulphoxide 194 in 78% yield ° (equation 103). 

The measurements that have been made at Rochester and the experience that has been gathered over the years on the operation of sputter ion sources [38] indicate that an analytical tool of unprecedented sensitivity and accuracy for isotopic ratio determinations can be constructed by coupling SIMS technology with the new accelerator technique. The only difference in principle between the experiments that have been conducted to date and the technique as it would be applied in secondary ion mass spectrometry is that the primary beam of cesium would be focussed to a fine probe of pm dimensions rather than the spot diameters of approximately 1 mm that have been used to date. 

Cesium salts of 12-tungstophosphoric acid have been compared to the pure acid and to a sulfated zirconia sample for isobutane/1-butene alkylation at room temperature. The salt was found to be much more active than either the acid or sulfated zirconia (201). Heteropolyacids have also been supported on sulfated zirconia catalysts. The combination was found to be superior to heteropolyacid supported on pure zirconia and on zirconia and other supports that had been treated with a variety of mineral acids (202). Solutions of heteropolyacids (containing phosphorus or silicon) in acetic acid were tested as alkylation catalysts at 323 K by Zhao et al. (203). The system was sensitive to the heteropoly acid/acetic acid ratio and the amount of crystalline water. As observed in the alkylation with conventional liquid acids, a polymer was formed, which enhanced the catalytic activity. 

Furthermore, the first catalytic synthesis of allenes with high enantiomeric purity [15c, 25] was applied recently to the pheromone 12 by Ogasawara and Hayashi [26] (Scheme 18.7). Their palladium-catalyzed SN2 -substitution process of the bromo-diene 16 with dimethyl malonate in the presence of cesium tert-butanolate and catalytic amounts of the chiral ligand (R)-Segphos furnished allene 17 with 77% ee. Subsequent transformation into the desired target molecule 12 via decarboxylation and selenoxide elimination proceeded without appreciable loss of stereochemical purity and again (cf. Scheme 18.5) led to the formation of the allenic pheromone in practically the same enantiomeric ratio as in the natural sample. 

A similar analysis was conducted by Fujimura et al. on cesium-neutralized Nafion with orientations up to Ab = 1.5 (where Ab is the ratio of the final extended length to the initial undrawn length). Over a range of orientations, the ionomer peak was observed to shift to lower angles and decrease in intensity in the meridional (draw) direction, while a shift to higher angles and an increase in intensity... 

Reaction with sodium or potassium hydroxide forms trans-osmate ion, trans-[0s04(0H)2]2 , which is reduced by ethanol to form dark purple [0s i(0)2(0H)4]2 . On the other hand, reaction of osmium tetroxide with rubidium or cesium hydroxide in stoichiometric ratios usually form the ions, [0s04(0H)] and [0s0( j,-0H)0s04] in addition to trans-[0s04(0H)2]27... 

The Ru/Rh/Cs/HOAc Catalyst Composition. Table I illustrates the effect, on product distribution and catalytic activity, of the incremental addition of cesium ions to a catalyst precursor composition containing ruthenium and rhodium, in the molar ratio of 10 1, dissolved in glacial acetic acid. The results of control experiments, in which no cesium is present, are also included. 

Fig. 8. Plot of rates as a function of Cst/Rh ratio ( ) methanol ( ) ethylene glycol. Reaction conditions 75 ml tetraglyme solvent, 3 mmol Rh, 10 mmol 2-hydroxypyridine, 544 atm, H2/CO = 1, 220 C, cesium formate promoter as indicated, 4 hr (88). Methanol and ethylene glycol rates at Cs+/Rh = 0 are 5.21 and 1.34 hr-1, respectively.

A still more complete insight into the nature of adsorbed species can be obtained from experiments (I) on thermionic emission, ( ) with the field emission microscope, and (S) with the ion gauge. From some thermionic experiments, particularly with cesium adsorbed on tungsten, it is learned that (a) Cs can be adsorbed as positive ions as well as adatoms (b) as the concentration of adsorbed cesium increases, the ratio of adions to adatoms decreases (c) the forces produced by adions are long-range forces which have appreciable effects over distances of 10 to 20 atom diameters (d) adatoms and adions can migrate over the surface at much lower temperatures than those at which they evaporate from the surface. 

The reaction of 17/ -estradiol (14) with cesium fluoroxysulfate and boron trifluoride-diethyl ether complex in acetonitrile gives the 2-fluoro and 4-fluoro isomers in a 1 1 ratio,17 while the reaction with the hexamethyl ether of gossypol fails under a variety of conditions.21... 

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