Lithium, rubidium and caesium

These elements are present at significant concentrations only in mineral and sea waters. Lithium accumulates in plants and can inhibit their growth. Therefore, some countries recommend limiting the content of lithium in waters intended for irrigation. Lithium has a certain balneological importance, and is employed in the prevention of coronary diseases caused by atherosclerosis. 

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Exotic Salts of Lithium, Rubidium and Caesium and their Formulations... 

Lithium, rubidium, and caesium.—F. C. Robinson and C. C. Hutchins 7 extracted all three alkalies—lithium, rubidium, and caesium—by decomposing the mineral with fluorspar in the following manner ... 

The alkali sulphates can also be made by neutralizing, say, a soln. of 5 grms. of sulphuric acid in 30 c.c. of water with the alkali hydroxide or carbonate, and evaporating the soln. until crystals begin to form. The process is not economical except on a small scale. It is used mainly for lithium, rubidium, and caesium sulphates. H. Erdmann 20 treated a hot soln. of crude rubidium iron alum with milk of lime made from purified lime, and filtered the liquid from the excess of lime, calcium sulphate, and ferric hydroxide, by suction. The small amount of lime in soln. is precipitated by adding rubidium carbonate. The filtrate is neutralized with sulphuric acid, and evaporated to the point of crystallization. 

V. 1 Olivier a trace of iodine. L. Dieulafait found traces of lithium, rubidium, and caesium salt H. Beckurts, chlorates and perchlorates up to 5 64 per cent. M. Marcker, borates and humus C. F. Schfinbein, nitrites and ammonia R. Wagner, iodine and bromine. H. Griineberg says the former is present as iodate or periodate. 

Horstman, E. L. The distribution of lithium, rubidium, and caesium in igneous and sedimentary rocks. Geochim. cosmochim. Acta 12, 1 (1957). 

Compounds of Group I. — There is a general resemblance between the compounds of the elements of the alkali group. The chief distinctive features of the compounds of lithium, rubidium, and caesium have already... 

The alkali metals form a homogeneous group of extremely reactive elements which illustrate well the similarities and trends to be expected from the periodic classification, as discussed in Chapter 2. Their physical and chemical properties are readily interpreted in terms of their simple electronic configuration, ns, and for this reason they have been extensively studied by the full range of experimental and theoretical techniques. Compounds of sodium and potassium have been known from ancient times and both elements are essential for animal life. They are also major items of trade, commerce and chemical industry. Lithium was first recognized as a separate element at the beginning of the nineteenth eentury but did not assume major industrial importance until about 40 y ago. Rubidium and caesium are of considerable academic interest but so far have few industrial applications. Francium, the elusive element 87, has only fleeting existence in nature due to its very short radioactive half-life, and this delayed its discovery until 1939. 

Reactivity towards air or oxygen increases from lithium to caesium, and the intensity depends on state of subdivision and on presence or absence of moisture. Lithium normally ignites in air above its m.p., while potassium may ignite after exposure to atmosphere, unless it is unusually dry. Rubidium and caesium ignite immediately on exposure [1], It is reported that sodium and potassium may be distilled unchanged under perfectly dried oxygen [2],... 

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... 

Monorubium acetylide and monocaesium acetylide incandesce with warm phosphorus. Lithium acetylide and sodium acetylide bum vigorously in phosphorus vapour, and the potassium, rubidium and caesium analogues should react with increasing violence. 

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],... 

A remarkable property of the atomic weights was discovered, in the sixties, independently by Lothar Meyer and Mendeleeff. They found that the elements could be arranged in rows in the order of their atomic weights so that similar elements would be found in the same columns. A modernised form of the Periodic Table will be found on pp. 106, 107. It will be noticed, for example, that the "alkali" metals, Lithium, Sodium, Rubidium and Caesium, which... 

Heats of solution, hydration energies and lattice energies are discussed in reference (77). For oxygen and nitrogen donor atoms, only a few compounds of potassium, rubidium, and caesium are known, but several have been characterised for the smaller cations, sodium and lithium. 

The properties of the alkali metals and of their salts are roughly functions of the at. wt. of the metals. There is generally a break in the curve about potassium so that lithium and sodium form one series, and potassium, rubidium, and caesium another. The properties of the series, K, Rb, Cs generally change more regularly than the series Li, Na, K, although some irregularities do occur—e.g. the m.p. of the nitrates. 

The electro-affinity of lithium is smaller than that of any of the other alkali metals, and it exhibits a greater tendency than the other alkali metals to form complex salts—e.g. the solubility of ammonia in water is raised by the addition of a lithium salt, which presumably unites with the ammonia the solubility curves of the lithium salts in water usually show more breaks than the corresponding salts of the other alkali metals owing to the formation of hydrates. Potassium, rubidium, and caesium seem to have a smaller and smaller tendency to form complex salts as the at. wt. of the element increases otherwise expressed, the electro-affinity, or the ionization tendency of the alkali metals increases as the at. wt. increases. This is illustrated by the heats of ionization. According to W. Ostwald,27 the heat of ionization per gram-atom iB... 

The replacement of potassium by rubidium, or rubidium by csesium, produces a regular increase in the dimensions of the crystal, and the same regularities occur in the optical properties. The same regularities do not occur with sodium and lithium. A. Ogg and F. L. Hopwood have calculated the lengths of the sides and the volume of the unit rhomb of the crystals potassium, rubidium, and caesium sulphates from data furnished by the X-ray spectrometer they find... 

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