Caesium ion

Chemical shifts in nuclear resonances of caesium ions in solution, Proc. Royal Soc. London. 313 45 (1969). 

No extensive comparison with experiment to test the values in Table IV will be made. The close agreement between the purely theoretical and the experimental results in the case of helium and neon allows one to place confidence in the R values for ions with these structures and the same remark applies with less force in the case of the argon structure, where only a small empirical correction was introduced. It is interesting to note that the theoretical values 3-57 and 6-15 for the rubidium and the caesium ion agree very well with the experimental ones, 3-56 and 6-17 (Table III), which were not used at all in the evaluation of the empirical corrections for these structures. Finally, we may mention that our values agree in general with those of Fajans and WulfE.i obtained by them from the experimental R values for salt solutions by the application of only the simplest theoretical considerations. 

A.K. Jain, R.P. Singh, and C. Bala, Studies on an Araldite-based membrane of copper hexacyanoferrate(III) as a caesium-ion-sensitive electrode. J. Chem. Technol. Biotechnol., Chem. Technol. 34A, 363—366 (1984). 

The e.s.r. spectra of phosphorus compounds have been reviewed.101 The phosphorus hyperfine splitting (ap 33.5 G) of the radical anion (77) is within the 25—36 G range of phosphorin radical anions.102 The cis- and fra/w-isomers of 1,2-bisdiphenylphos-phinoethylene gave the same radical anion (78). The unpaired electron is coupled to all the protons in the molecule as well as to the two phosphorus atoms, and shows that the electron is completely delocalized. Only when caesium was used as the gegenion in THF could a metal interaction be detected. The spectrum in this case corresponded to the association of two caesium ions with the radical anion, the third... 

Due to the high interest in metalation reactions with lithium amide or alkyllithiums, an indicator scale of lithium ion pairs in THF has been developed119. Aggregation studies have indicated that organolithium species exist predominantly, if not exclusively, as monomers in the 10-3-10-4 M concentration range. Particular attention has been devoted to the lithium and caesium ion-pair acidities of diphenylamine in THF120 that, at 25 °C, have been found to be 19.05 and 24.20, respectively. 

A unit cell of the caesium chloride structure is shown in Figure 1.30. It shows a caesium ion, Cs, at the centre of the cubic unit cell, surrounded by eight chloride... 

As you might expect from their relative positions in Group I, a sodium ion is smaiier than a caesium ion and so it is now only possible to pack six chlorides around it and not eight as in caesium chloride. 

The structure of [Cs(ri -PhMe)3(p-F)In N(SiMe3)2 3] features a distorted tetrahedral indium connected to a caesium ion via a bridging p2-F ligand with In—F and Cs—F bond lengths of 2.065(2) and 2.777(2) A, respectively (Figure 8.10). The In—N bond lengths are 2.12 and 2.13 A. The caesium has additional Cs-arene interactions with three toluene solvent molecules (average Cs-Caryi distances are ca 3.81 A). 

The sample, introduced in a solid form, is bombarded by caesium ions. The first mass analyser is used to extract negative ions at selected masses. The ions are then accelerated through a potential difference of several megavolts to eliminate isobaric... 

Not all ionic substances form the same structures. Caesium chloride (CsCl), for example, forms a different structure due to the larger size of the caesium ion compared with that of the sodium ion. This gives rise to the structure shown in Figure 3.16, which is called a body-centred cubic structure. Each caesium ion is surrounded by eight chloride ions and, in turn, each chloride ion is surrounded by eight caesium ions. 

We saw in Fig. 6-30 the conversion of ethylene oxide to crown ethers upon reaction with appropriate metal salts, and demonstrated that the hole sizes of the products corresponded to the ionic radius of the template ion. However, lest we become over-confident, it should be pointed out that the major product from the reaction of ethylene oxide with caesium salts (r = 1.67 A) is not the expected 21-crown-7 with a hole size of about 1.7 A) but 18-crown-6 (hole size, 1.4 A) (Fig. 6-34). The reason for this lies in the structure of the complex formed. We have always assumed that the metal ion will try to lie in the middle of the bonding cavity of the macrocycle. There is no real reason why this should be. Caesium could form a complex with 21-crown-7 in which all of the oxygen atoms lie approximately planar with the metal in the centre of the cavity. It is also apparent that caesium could not occupy the middle of the cavity in 18-crown-6. However, a different type of complex can be formed with 18-crown-6, in which a caesium ion is sandwiched bet-... 

Forty different compositions of solution were studied (Figure 1) with special emphasis on nine representative solutions (shown in the boxes of Figure 1). The compositions of these nine solutions are given in Table I. Solutions containing sodium, potassium, rubidium or caesium ions were studied. 

K6nya, J., N. M. Nagy, and Z. Nemes. 2005. The effect of mineral composition on the adsorption of caesium ion on geological formations. J. Coll. Interface Sci. 190 350-356. 

Caesium Ion.—Caesium forms colourless univalent ions. It is the most electropositive of the elements, its great electroaffinity corresponding with the ready solubility of its salts. The salts with strong anions are less soluble than the corresponding derivatives of the other alkali-metals.11... 

In a recent study [175] of the methoxide ion catalysed tritium exchange in methanol of weakly acidic fluorinated bicycloalkanes (pIT ca. 20), comparison of the rates of exchange for six compounds, with ion-pair pK values determined in cyclohexylamine containing caesium ions, gave a Bronsted plot with slope (a) within experimental error of unity. The isotope effects for proton compared with deuteron transfer (feH/feD = 1.2) are similar to those observed with chloroform. The charge on these polyfluorocarbanions may also be localized on carbon [175]. 

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