Cesium interatomic distance

Solution X-ray diffraction measurements for saturated aqueous solutions of the KCl-MgCl2-6H20 and CsCl-MgCl2-6H20 double salts at 25°C reveal that magnesium(II) ions in the solutions are fully hydrated as [Mg(H20)6]2+ with a Mg-0 bond length of 208-209 pm. This is essentially the same bond length as in the double salt crystals, and the K+ and Cs+ ions have both water molecules and chloride ions in their first coordination sphere. The coordination numbers for water molecules and chloride ions around a K+ ion are 4.7 and 2.4, respectively, and those around a Cs+ ion are 4.7 and 2.0, respectively. The K+-OH2 and K+-C1 interatomic distances are found to be 227 and 320 pm, respectively, and the Cs+-OH2 and Cs + -Cl distances are 315 and 339 pm, respectively (58). The interatomic distances determined are essentially the same as those that have been reported in the literature for aqueous solutions of potassium and cesium salts. 

Hawthorne and coworkers. However, the interatomic distances of Cs to the carborane cages are such that it could be regarded as a cesium-carborane complex in which some degree of interaction exists between the metal and the 7C-electron density on the carborane cage. Since this cesium compound can also be prepared by an ion-exchange reaction directly from lithium, sodium or potassium salts of the C B -cage (see Figure 6b), further study of this and related compounds in solvent extraction of radioactive cesium metal ( Cs) from nuclear waste is envisioned. 

Tables 2.1-2.4 relative to sodiiun, lithium, potassium, rubidium, and cesium salts, also show that, in general, the values of a obtained by fitting experimental data of activity coefficients are larger than the sum of ionic radii in solutions (or crystal-lattice spacing) and the interatomic distances, d. Also they are close to the values obtained from Kielland sdata and toab initio values calculated by using two models model I and model II, considering the absence and the presence of five water molecules between anion and cation, optimized in the gas phase, respectively), and also to those obtained fi om MM studies, where no water molecules are consid-...

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