Caesium chloride

Rock salt Rutile Caesium chloride Fluorite... 

Thermodynamic data show that the stabilities of the caesium chloride-metal chloride complexes are greater than the conesponding sodium and potassium compounds, and tire fluorides form complexes more readily tlrair the chlorides, in the solid state. It would seem that tire stabilities of these compounds would transfer into tire liquid state. In fact, it has been possible to account for the heats of formation of molten salt mixtures by the assumption that molten complex salts contain complex as well as simple anions, so tlrat tire heat of formation of the liquid mixtures is tire mole fraction weighted product of the pure components and the complex. For example, in the CsCl-ZrCU system the heat of formation is given on each side of tire complex compound composition, the mole fraction of the compound... 

I. S. Barnes, S. T. Hyde, B. W. Ninham. The caesium chloride zero potential surface is not the Schwarz P-surface. J Physique Colloque 51 C7 19-24, 1990. 

Caesium chloride is not body-centered cubic, but cubic primitive. A structure is body centered only if for every atom in the position x, y, z there is another symmetry-equivalent atom in the position x+ j,y+ j,z+ j in the unit cell. The atoms therefore must be of the same kind. It is unfortunate to call a cluster with an interstitial atom a centered cluster because this causes a confusion of the well-defined term centered with a rather blurred term. Do not say, the 04 tetrahedron of the sulfate ion is centered by the sulfur atom. 

Vandecasteele et al. [745] studied signal suppression in ICP-MS of beryllium, aluminium, zinc, rubidium, indium, and lead in multielement solutions, and in the presence of increasing amounts of sodium chloride (up to 9 g/1). The suppression effects were the same for all of the analyte elements under consideration, and it was therefore possible to use one particular element, 115indium, as an internal standard to correct for the suppressive matrix effect, which significantly improved experimental precision. To study the causes of matrix effect, 0.154 M solutions of ammonium chloride, sodium chloride, and caesium chloride were compared. Ammonium chloride exhibited the least suppressive effect, and caesium chloride the most. The results had implications for trace element determinations in seawater (35 g sodium chloride per litre). 

The materials usually used to produce such gradients are salts of heavy alkali metals, caesium chloride being the most frequently used. This salt has a high solubility and its low relative molecular mass permits rapid diffusion enabling the gradient to be formed reasonably quickly. Concentrations of salt up to about 2 g ml-1 can be used and are chosen on the basis of information about the density of the test particles or macromolecules. The technique is used frequently in the separation of viral particles and nucleic acids. 

Figure 13.7 Caesium chloride density gradient centrifugation for (a) the separation of DNA from RNA and protein and (b) the separation of linear DNA and supercoiled DNA.

RNA and DNA are isolated from tissues using caesium chloride density gradient sedimentation... 

Total RNA can be prepared using commercially available kits according to the protocols of the manufacturer or by the guanidinium isothiocyanate method, followed by caesium chloride centrifugation (CsCl). Details are published in handbooks of molecular biology techniques. In our hands, both methods are equivalent, but if budgets are limited, the CsCl method may be more suitable for the preparation of large amounts of RNA. 

The reaction between dry phosphine and hydrogen iodide, first described in 1817 by J. J.Houtonde la Billardiere produces phosphonium iodide. The simplest laboratory preparation of this compound is by the hydrolysis of an intimate mixture of diphosphorus tetraiodide and white phosphorus According to X-ray diffraction investigations, phosphonium iodide crystallises in a caesium chloride type lattice 3m,32s). 326) hydrogen atoms... 

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 tonic compound caesium chloride, Cs + CI-, dissolves readily in water to give a solution containing the individually hydrated Cs+ (aq) and Cl-(aq) ions. The thermodynamic parameters for the formation reaction of Cs hCl and for the reaction of its solution in water are ... 

The electrical conductivities of soln. of a great many compounds in liquid hydrogen halides have been measured by E. H. Archibald and D. McIntosh. The conductivity is raised considerably by phosphoryl chloride. Sodium sodium sulphide, borate, phosphate, nitrate, thiosulphate, and arsenate chromic anhydride potassium nitrate, hydroxide, chromate, sulphide, bisulphate, and ferro- and ferri- cyanide ammonium fluoride and carbonate j rubidium and caesium chloride magnesium sulphate calcium fluoride ... 

To make this quite clear, suppose that 5 grms. of a compound, supposed to be potassium chloride, are obtained. This will he multiplied by 0 631 to get the eq. amount, 3-16 grms. of KaO but if the compound be CsCl, not KCl, then the weight must be multiplied by 0-835 to get the corresponding amount, 4T8 grms. of CsaO. The analysis would thus appear to be 4T8 less 3T6, that is 1-02 grms. too low if the 6 grms. of caesium chloride were mistaken for potassium chloride. This is a remarkable tribute to the accuracy of Plattner s analysis. 

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