Rubidium and Cesium

Systematizing these results, we see that both in Fig. 72 and in Fig. 73, if we follow tho succession of curves from top to bottom, we go from ions of dissimilar character to ions of similar character in Fig. 73 we go down to Li+ and (Oil)", both strong order-producing ions, while in Fig. 72 we go down to Cs+ and Br", both strong order-destroying ions. If the same rule—from dissimilar character downward to similar character— is to be applied to the rubidium and cesium halides, the order I, Br, Cl, F, will clearly have to be reversed, in order that Rbl and Csl shall be the lowest in each case. It has been known for several years that such an inversion exists. Table 40, compiled by Robinson and Harned, shows the order observed in the whole set of iodides, bromides, and chlorides. It will be seen that, for RbCl, RbBr, and Rbl, and likewise for CsCl, CsBr, and Rbl, the observed order is opposite to that found for the other alkali halides. Hitherto this inversion has been regarded as mysterious. But it falls in line with the facts depicted in Fig. 72,... 

In addition, it should be noted that K2Nb03F is less stable that its rubidium and cesium analogs and that it too decomposes at relatively high temperatures, as follows ... 

A slight but systematic decrease in the wave number of the complexes bond vibrations, observed when moving from sodium to cesium, corresponds to the increase in the covalency of the inner-sphere bonds. Taking into account that the ionic radii of rubidium and cesium are greater than that of fluorine, it can be assumed that the covalent bond share results not only from the polarization of the complex ion but from that of the outer-sphere cation as well. This mechanism could explain the main differences between fluoride ions and oxides. For instance, melts of alkali metal nitrates display a similar influence of the alkali metal on the vibration frequency, but covalent interactions are affected mostly by the polarization of nitrate ions in the field of the outer-sphere alkali metal cations [359]. 

Whereas technique (4) works for all alkali metals, lithium and sodium behave differently from potassium, rubidium, and cesium with respect to graphite on direct combination. The last three react facilely with graphite, to form compounds CgM (first stage) and Ci2 M (stage n > 1), but lithium reacts only under more extreme conditions of temperature or pressure, or both, to form compounds of formula CenLi (G3,... 

X-ray crystallography of potassium, rubidium, and cesium methyls shows completely ionic crystal lattices Weiss, E. Sauermann, G. Chem. Ben, 1970, 103, 265 Weiss, E. Koster, H. Chem. Ber., 1977, 110, 717. 

Flow boiling of other alkali metals CHF data for other alkali metals were reported by Fisher et al. (1964, 1965), who tested rubidium and cesium in axial and swirl flow and potassium in swirl flow. The data were correlated by postulating a mist or fog flow model for the hydrodynamic situation in the heated section in which CHF occurs. These investigations were motivated by the potential use of alkali metals as Rankine cycle working media in space applications and have not been pursued further, because there is no longer interest in such concepts. 

Achener, P. Y., 1964, The Determination of the Latent Heat of Vaporization, Vapor Pressure, Enthalpy, and Density of Liquid Rubidium and Cesium up to 1,800°F, Proc. 1963 High Temperature Liquid Metal Heat Transfer Technology Meeting, Vol. 1, pp. 3-25 USAEC Rep. ORNL-3605. (2) Achener, P. Y, 1965, The Determination of the Latent Heat of Vaporization, Vapor Pressure of Potassium from 1,000-1,900°F, Aerojet-General Nucleonics Rep. AGN-8141. (2)... 

Tepper, F., A. Murchison, J. Zelenak, and F. Roehlich, 1964, Thermophysical Properties of Rubidium and Cesium, Proc. 1963 High Temperature Liquid Metal Technology Meeting Vol. 1, 26-65, US AEC Rep. ORNL-3605. (5)... 

The 02 ion is known as the superoxide ion, and it is produced when oxygen reacts with potassium, rubidium, and cesium. 

This reaction is also true for rubidium and cesium. (Note These are superoxides.)... 

VIOLET Potassium compounds other than silicates, phosphates and borates rubidium and cesium are similar. Color is masked by lithium and/or sodium, appears purple-red through cobalt glass and bluish-green glass. 

Helmke PA, Sparks DL. Lithium, sodium, potassium, rubidium, and cesium. In Bartels JM (ed.), Methods of Soil Analysis Part 3 Chemical Methods. Madison, WI ... 

Fig. 1. Mean reduced vapor pressure curve for the halides of sodium, potassium, rubidium, and cesium. Average deviation from the mean is shown by the vertical lines.

Alkali metals, especially potassium, rubidium, and cesium Metal amides (e.g., NaNH2)... 

Metals react with nonmetals. These reactions are oxidation-reduction reactions. (See Chapters 4 and 18). Oxidation of the metal occurs in conjunction with reduction of the nonmetal. In most cases, only simple compounds will form. For example, oxygen, 02, reacts with nearly all metals to form oxides (compounds containing O2-). Exceptions are the reaction with sodium where sodium peroxide, Na202, forms and the reaction with potassium, rubidium, and cesium where the superoxides, K02, Rb02, and Cs02 form. 

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