MAGNESIUM.160 RUBIDIUM CHLORIDE

Rubidium metal may be obtained from its carbonate, hydroxide or chloride by reduction with magnesium or calcium at high temperatures in the presence of hydrogen ... 

In 1863 R. C. Bottger of Frankfort-on-the Main found that thallium occurs in some spring waters. A certain salt mixture from Nauheim contained, in addition to the chlorides of sodium, potassium, and magnesium, those of cesium, rubidium, and thallium. Since he was able to prepare a thallium ferric alum exactly analogous to potassium ferric alum, he regarded thallium as an alkali metal (72, 73). Although it is sometimes univalent like sodium and potassium, it is now classified in Group III of the periodic system. 

The electrical conductivities of soln. of a great many compounds in liquid hydrogen halides have been measured by E. H. Archibald and D. McIntosh. The conductivity is raised considerably by phosphoryl chloride. Sodium sodium sulphide, borate, phosphate, nitrate, thiosulphate, and arsenate chromic anhydride potassium nitrate, hydroxide, chromate, sulphide, bisulphate, and ferro- and ferri- cyanide ammonium fluoride and carbonate j rubidium and caesium chloride magnesium sulphate calcium fluoride ... 

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. 

The sodium chloride structure is adopted by most of the alkali metal halides All of the lithium, sodium, potassium, and rubidium halides plus cesium fluoride It is also found in the oxides of magnesium, calcium, strontium, barium, and cadmium... 

The effect of other electrolytes is also of interest. Addition of divalent cations, e.g., in the form of calcium and magnesium chloride salts, results in precipitation of the anionic vesicles, which is also observed for micelles in water. There is, however, a significant trend within the alkali metal cations, e.g., from Na+ to Rb+. The larger rubidium ion has a promotional effect on the formation of vesicles, and indeed with Cs+, vesicles are already formed on the addition of trace amounts of salt. The relevant data are shown in Fig. 19.8. 

The potassium salt is the most soluble, whilst the caesium salt is quite insoluble in water. Both the rubidium and the caesium salts may be prepared by double decomposition of dilute solutions of their chlorides with the nitroso salts of sodium or potassium. The thallium salt may be prepared in a similar manner by means of thallium sulphate. The nitroso salts of the alkaline earth metals—calcium, barium, and magnesium—are very soluble in water. 

The wet oxide reacts explosively with molten aluminum-magnesium aUoys. Violent reaction when heated with powdered aluminum, calcium disilicide, magnesium, metal acetyKdes (e.g., calcium acetyKde + iron(III) chloride (on ignition), cesium acetyKde (incandescent reaction when warmed), rubidium acetyKde). Reacts violently with Al, Ca(OCl)2, N2H4, ethylene oxide. See also IRON and IRON COMPOUNDS. 

Metallurgy. — Metallic, rubidium may be prepared in a variety of ways (1) electrolysis of the fused chloride, (2) heating RbOH with aluminium or mugnesinin, fH) heating Rb,t 0 with carhon or magnesium, (4) heating It Iff 1 wilh calcium, (5) heating the tartrate to white heat. 

ETHYLIDENE CHLORIDE or ETHYLIDENE DICHLORIDE or 1,1-ETHYLIDENE DICHLORIDE (75-34-3) C2H4CI2 Forms explosive mixture with air [explosion limits in air (vol %) 5.6 to 11.4 flash point 10°F/-12°C autoignition temp 856°F/458°C Fire Rating 3], Violent reaction with strong oxidizers, potassium powdered metals alkaline earth (barium, calcium, strontium sometime magnesium is included) and alkali metals (lithium, sodium, potassium, rubidium, cesium, and francium). Contact with strong caustics will cause... 

The calcium carbonate, magnesium carbonate, potassium carbonate, potassium chloride, potassium hydroxide, sodium carbonate, and rubidium carbonate were anhydrous reagent grade materials. They were used as received. 

Potassium carbonate (runs 4-97, 4-109, 5-24, and 5-44) and the similar rubidium carbonate (run 4-120) promoted the synthesis of fatty acids. The other carbonates, i.e., calcium carbonate (run 4-106), sodium carbonate (run 4-107), magnesium carbonate (run 5-27), and potassium chloride (run 4-114), did not produce fatty acids. Small amounts of fatty acids were obtained when potassium hydroxide (run 5-32) was used. However, some potassium carbonate was produced in situ in this reaction. 

The direct metallothermic reduction of pollucite ore with sodium metal is the primary commercial source of cesium metal. In the process, raw pollucite ore is reduced with sodium molten metal at ca. 650"C to form a sodium-cesium alloy containing some rubidium as impurity. Fractional distillation of this alloy in a distillation column at ca. 700"C produces 99.9 wt.% pure cesium metal. Cesium can also be obtained pyrometallurgiccdly reducing the chloride CsCl with calcium metal or the hydroxide CsOH with magnesium metal. Nevertheless, the electrolytic recovery of a cesium amalgam from an aqueous solution of cesium chloride can be achieved in a process similar to the chlor-alkali production with a mercury cathode. Afterwards, the cesium is removed from the amalgam by vacuum distillation. However, cesium metal is produced in rather limited amounts because of its relatively high cost (US 40,800 /kg)... 

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