Caesium detection

Phosphorus-sulphur type - - Alkali metal thermionic Melpar (rubidium-caesium) detection - [404]... 

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... 

T. Scheerer found that when heated to a yellow heat (c.1000°), in a closed platinum crucible, potassium carbonate loses about 0 5 per cent, in weight owing to the loss of carbon dioxide which is taken up again at lower temp. W. Dittmar could detect no change when heated to redness in an atm. of carbon dioxide, but it is partially converted into oxide in an atm. of nitrogen, and still more so in an atm. of hydrogen. P. Lebeau found that rubidium and caesium carbonates lose carbon dioxide when heated in vacuo, and, if the vacuum be maintained, decomposition is complete. P. Lebeau also found that the dissociation press, of rubidium carbonate is ... 

After Bunsen had detected and isolated caesium, spectroscopy was taken up with great enthusiasm by William Crookes, and this led to his detection and isolation of thallium in 1861.191 Crookes letters to Charles Hanson Greville Williams, who was also working with the spectroscope, and who felt he deserved some of the credit for the discovery of thallium, have been published.192 The use of spectrochemistry in the search for hitherto unknown chemical elements in Britain over the period 1860-1869 has been described. It was perceived that, like Crookes, a scientist could make his reputation by discovering a new element. This resulted in several claims for the existence of new elements that later proved to be unfounded.193 Once Kirchhoff had established beyond doubt that the dark Fraunhofer lines were caused by the same element that caused emission lines of identical wavelengths, the way was open for the chemical analysis of the atmosphere of the sun and stars. This was a process which had been declared to be an impossibility by Auguste Comte less than 30 years previously.194... 

When total DNA is subjected to high speed density gradient centrifugation in caesium chloride, a large band of nuclear DNA and one or more small satellite bands are usually observed. Up to four satellite DNA bands have been detected in... 

The most sensitive flame spectrometric procedure for the determination of strontium is FES, the emission intensity at 460.7 nm being measured from a nitrous oxide-acetylene flame. A detection limit of 1 ng ml-1 or better is generally readily attainable, although the element has a low ionization potential and addition of potassium or caesium at a final concentration of 2-5 mg ml 1 is essential as an ionization buffer. Chemical interference from phosphate, silicate and aluminium is reduced dramatically in this flame. 

Pentachlor-platmous Acid has not as yet been isolated in a free state although its presence has been detected in solution 4 when chlorine is passed into a solution of tetrachlor-platinous acid, since it yields with caesium chloride the characteristic green precipitate of caesium penta-chlor-platinite, Cs2PtCl5, which is the only salt of this acid at present known. 

The salts of sodium react with a solution of potassium nitrite and the nitrates of bismuth and caesium, yielding a yellow, crystalline precipitate of the formula 5Bi(N02)3,9CsN02,6NaN02. This reaction is applicable to the detection and estimation of sodium.2... 

Caesium compounds impart a reddish-violet coloration to the Bunsen flame, similar to that given by rubidium. The chloride forms an insoluble double chloride with stannic chloride of the formula CsgSnCle,1 and also a double salt with antimony chloride.2 Mackenzie and Marshall s method 3 described for rubidium (p. 199) is also applicable to the detection of caesium.4... 

Bayer s microchemical method, mentioned in connexion with rubidium (p. 199) and caesium (p. 210), serves to detect one-hundredth of a microgram of silver. 

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