Rubidium tests

All the cations of Group I produce a characteristic colour in a flame (lithium, red sodium, yellow potassium, violet rubidium, dark red caesium, blue). The test may be applied quantitatively by atomising an aqueous solution containing Group I cations into a flame and determining the intensities of emission over the visible spectrum with a spectrophotometer Jlame photometry). 

Self-Test J.2A What acid and base solutions could you use to prepare rubidium nitrate Write the chemical equation for the neutralization. 

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. 

Bones of 19 individuals were analyzed for strontium, rubidium and zinc. The number of samples was limited by the availability of bone after the stable isotope analyses were completed. Strontium was analyzed in order to test for trophic level, and to compare to other results obtained in the region on prehistoric peoples (Katzenberg 1984). Rubidium is not expected in human bone, so its presence acts as a measure of contamination. The use of zinc as a paleodi-etary indicator has been questioned recently (Ezzo 1994) and we were interested to see if there was any relationship between zinc content in food and bone. 

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. 

Rubidium may be analyzed in an aqueous solution of rubidium carbonate by AA, ICP-AES or other methods (see Rubidium). Carbonate anion, COs may be measured quantitatively by ion chromatography. Additionally, COs may be tested by treating Rb salt with a dilute acid. Liberation of CO2 with effervescence that turns lime water milky is a qualitative test. 

When the five-hundredth anniversary of Heidelberg University was celebrated in 1886, an elaborate breakfast was served which lasted more than three hours. Bunsen fell asleep during one of the tiresome speeches, but at one place in the address the speaker s loud oratory caused the aged chemist to awake with a start. Rubbing his eyes, he whispered to his neighbor, I thought I had let a test-tube full of rubidium fall to the floor (11). 

Solutions of the alkali sulphides give a deep violet to purple coloration with a solution of sodium nitroprusside, and as mentioned on p. t. J, this may be used as a test for sulphides. By the interaction of the nitroprusside with the sulphides of lithium, sodium, potassium and rubidium, stable crystalline compounds of the type M4[Fc(CN)BNOS] have been obtained. From eleetrotitrimetric evidence the reaction appears to proceed in two stages 7... 

The reaction was carried out in dioxane, HMPA, and sulfolane as well as in mixtures of dioxane-DMSO (5 1 by volume) and water-DMSO (1 2) at 100-140°C with alkali metal (Li, Na, K, Rb, Cs) hydroxides, tetrabu-tylammonium hydroxide, and rubidium chloride examined as catalysts. All tests were run in an autoclave (1 L) at an initial acetylenic pressure of 12 atm. The most significant effect on the yield of 1-ethynylcyclo-hexanol (110) is that of the catalyst and the solvent. According to their diminishing efficiency, the catalysts examined are arranged as follows KOH RbOH > (Bu4)NOH > LiOH RbCl failed to catalyze the reaction and in the presence of CsOH, resinification was observed. The alcohol 110 is formed most readily in aqueous DMSO, dioxane being next in efficiency (with account for the yield based on the oxime consumed). Addition of DMSO to dioxane does not improve the yield of 110, and only trace amounts of this compound were obtained in HMPA and sulfolane. 

The ability of experimental agents to pass across the blood-brain barrier, log P, was determined according to the method of Hansch (2), inhibition constants, Kiy calculated using the method of Chang (3), and dopamine and rubidium ion release obtained calculated according to the method of Dull (4). Inhibition constants, dopamine and rubidium ion release testing results are provided in Table 2. 

Table 2 Test results of selected experimental agents indicating the ability of these materials to pass across the blood-brain barrier and impact on dopamine and rubidium ion release...

Compounds of sodium are readily identified by the yellow color that they give to a flame. Lithium causes a carmine coloration of the flame, and potassium, rubidium, and cesium cause a violet coloration. These elements may be tested for in the presence of sodium by use of a blue filter, of cobalt glass. 

Table II. Results of Homogeneity Tests for Rubidium (Rb) and Strontium (Sr) on the Standard Shale and a Spent Shale...

Use Analysis (testing for perchloric acid), source of rubidium metal. 

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