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Caesium preparation

The calibration curves for rubidium and caesium prepared according to this method display a relatively marked curvature. For this reason, following the first determination and using the Rb and Cs values obtained as a basis, the determination should be repeated with two new volumes of the sample, and so on. Using the pincer method the final values obtained are then... [Pg.282]

A 20 g sample, prepared and stored in a dry box for several months, developed a thin crust of oxidation/hydrolysis products. When the crust was disturbed, a violent explosion occurred, later estimated as equivalent to 230 g TNT. A weaker explosion was observed with potassium tetrahydroaluminate. The effect was attributed to superoxidation of traces of metallic potassium, and subsequent interaction of the hexahydroaluminate and superoxide after frictional initiation. Precautions advised include use of freshly prepared material, minimal storage in a dry diluent under an inert atmosphere and destruction of solid residues. Potassium hydrides and caesium hexahydroaluminate may behave similarly, as caesium also superoxidises in air. [Pg.53]

An explosive compound [1], and the preparation is hazardous, involving the fluori-nation of caesium perfluoropropoxide [2],... [Pg.389]

In the preparation of xenon difluoride dioxide from caesium nitrate and xenon tetrafluoride oxide, the latter must always be used in excess to prevent formation of explosive xenon trioxide. [Pg.1535]

Sodium hydride ignites in oxygen at 230°C, and finely divided uranium hydride ignites on contact. Lithium hydride, sodium hydride and potassium hydride react slowly in dry air, while rubidium and caesium hydrides ignite. Reaction is accelerated in moist air, and even finely divided lithium hydride ignites then [1], Finely divided magnesium hydride, prepared by pyrolysis, ignites immediately in air [2], See also COMPLEX HYDRIDES... [Pg.1848]

Removal of all possible contaminants is not the only reason for sample preparation, since each clean and purified material has then to be converted into the chemical form suitable for the accelerator ion source. In most cases (as explained in the previous section), samples are put into the caesium sputtering source as graphite, solid elemental carbon, and for this reason samples are first burnt and then chemically reduced to graphite. [Pg.474]

Any ions that need to be introduced into a sample either to prevent ionization or suppression effects (for example, a lanthanum and caesium mixture) or as an internal reference (for example, lithium) are usually incorporated in the diluting fluid in which the samples are prepared. [Pg.84]

The collected papers of a symposium at Dallas, April 1956, cover all aspects of the handling, use and hazards of lithium, sodium, potassium, their alloys, oxides and hydrides, in 19 chapters [1], Interaction of all 5 alkali metals with water under various circumstances has been discussed comparatively [2], In a monograph covering properties, preparation, handling and applications of the enhanced reactivity of metals dispersed finely in hydrocarbon diluents, the hazardous nature of potassium dispersions, and especially of rubidium and caesium dispersions is stressed [3], Alkaline-earth metal dispersions are of relatively low hazard. Safety practices for small-scale storage, handling, heating and reactions of lithium potassium and sodium with water are reviewed [4],... [Pg.33]

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. [Pg.581]

The structure of Helvite, Mn CBeSiOJjS, has been reported. The tetrahedral manganese ii) ions are bonded to one sulphur and three oxygen atoms. M2Mn3S4 (M = Rb or Cs) have been prepared by reactions in the molten state under nitrogen. An X-ray study on the caesium compound showed the manganese and caesium atoms to be arranged in layers separated by layers of sulphur atoms. ... [Pg.193]

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... [Pg.30]

Benzotriazole reacts with l-cyano-4-dimethylaminopyridinium bromide to give 1-cyano-benzotriazole (177) (Scheme 29) <88S470>. 1-Cyanobenzotriazole is also prepared in a more convenient way from cyanogen bromide and the sodium salt of benzotriazole in 90% yield under carefully controlled conditions <91RRC573>. Benzotriazole can be chlorinated at the N(l) position by NaOCl <85H(23)2225>. A-Fluorination of benzotriazole with caesium fluoroxysulfate gives 1-fluorobenzotriazole in 25% yield <91T7447>. [Pg.43]

A reaction of sulfoximine 268 with ort o-substituted halobenzaldehydes 269 takes place in the presence of a catalytic amount of Pd(ii), 2,2 -bis(diphenylphosphanyl)-l,l -binaphthyl (BINAP), and caesium carbonate at 110°C to afford fully conjugated 2-phenyl-2,l-benzothiazine 2-oxides 270 with a S(vi) oxidation state (Scheme 38) <1999AGE2419>. Bis-benzothiazine 75 has been prepared from dibromo-dialdehyde 271 in a similar manner and investigated as a ligand for Pd-catalyzed allylic alkylation reactions (see Section 8.07.12.3) <20010L3321>. [Pg.554]

As mentioned in Section 3.4, clusters of metal atoms of varying sizes can be prepared. The presence of alkali atom clusters in the vapour phase is well documented. Such clusters have a much lower ionization energy than that of an isolated atom and also have a high electron affinity. The probability of electron transfer is therefore considerably greater in a metal cluster. It is indeed known in the case of caesium that as the density of caesium increases (from isolated atoms in a low-density gas to a liquid), larger clusters form and charge-transfer becomes increasingly favoured as the density... [Pg.351]

Ammonium Dioxalato - diammino - chromium, [Cr(NH3)2 (C204)2]NH4.2H20, is obtained in red needles by acting upon dibromo-diaquo-diammino-chromic bromide with aqueous oxalic acid at a temperature of 60° C. The colour changes in solution to dark red and the salt separates. From the ammonium salt other salts may be prepared by treating an aqueous solution with metallic halide. The potassium salt crystallises in red needles containing two molecules of water the sodium salt crystallises in dark red prisms the lithium salt in red needles or leaflets and the caesium salt in dark red needles. These salts are very stable and may be reerystallised from water. [Pg.113]

Trifluoromethyl hypofluorite was first made by Cady by passing methanol [184] or carbon monoxide [185, 186] with fluorine over silver difluoride at elevated temperatures. Later, trifluoromethyl hypofluorite and higher perfluoroalkyl hypofluorites were prepared by treating the appropriate carbonyl compound with fluorine in the presence of dry caesium fluoride at sub-zero temperatures (Fig. 81) [187-189]. [Pg.31]

Uses Of the Stassfurt salts.—The magnesium compounds in the Stassfurt salts are used for the preparation of magnesium and of its salts. The potash salts are an essential constituent of many fertilizers used in agriculture, etc. 22 and potassium chloride is the starting-point for the manufacture of the many different kinds of potassium salts used in commerce—carbonate, hydroxide, nitrate, chlorate, chromate, alum, ferrocyanide, cyanide, iodide, bromide, etc. Chlorine and bromine are extracted by electrolysis and other processes from the mother liquids obtained in the purification of the potash salts. Boric acid and borax are prepared from boracite. Caesium and rubidium are recovered from the crude carnallite and sylvite. [Pg.435]


See other pages where Caesium preparation is mentioned: [Pg.130]    [Pg.76]    [Pg.1521]    [Pg.18]    [Pg.36]    [Pg.352]    [Pg.159]    [Pg.130]    [Pg.16]    [Pg.333]    [Pg.147]    [Pg.196]    [Pg.215]    [Pg.49]    [Pg.190]    [Pg.168]    [Pg.270]    [Pg.18]    [Pg.30]    [Pg.333]    [Pg.395]    [Pg.406]    [Pg.408]    [Pg.417]    [Pg.424]    [Pg.449]    [Pg.450]    [Pg.473]    [Pg.482]    [Pg.486]    [Pg.488]   
See also in sourсe #XX -- [ Pg.200 ]




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Caesium

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