Strontium amalgam

Alloys are metallic substances containing two or more elements which are miscible when molten and do not separate when solidified. They may be liquid or solid. This mixture of elements, usually but not necessarily metals, allows careful manipulation of strength, melting point, corrosion resistance, magnetic, thermal, electrical, and other properties steel, for example, is an alloy of iron and carbon often present with nickel, chromium, copper, aluminium, boron, tungsten, manganese, cobalt, silicon, and other elements. 

Alkali metal alloys and alkaline earth metal alloys have a wide range of applications. The degree to which the alloys retain the pyrophoric or water-reactive properties of their parent metals depends on their concentration in the alloy, the modifying nature of the alloyed components, and the state of subdivision. Many commercial alloys of this type, present no hazard. Others, such as the potassium-sodium alloys used in heat exchangers, present significant concern. Other alkali and alkaline earth metal alloys include 

Amalgams are alloys of mercury with other metals used extensively as chemical reagents and catalysts. The proportion of mercury dictates whether the amalgam is solid or liquid. They include sodium amalgam (Na Rgy), used to manufacture sodium hydroxide, and dental amalgams (alloys of mercury with some combination of silver, copper, tin, gold, or silver) used to fill dental cavities. 

Alkali metal, see Terminology, Metals, p.242 Alkaline earth metal, see Terminology, Metals, p.242 

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Silicon, higher chlorides of, 42 Silicon tetrabromide, 38, 40 Silicon tetrachloride, 44 Silicopropane, octachloro, 44 Silicotungstic acid, 129 analysis, 131 ether complex, 131 Silver, metallic, 4 Silver chloride, reduction of, 3 Silver cyanamide, 98 Silver residues, purification of, 2 Sodium amalgam, 10 Sodium amide, 74 Sodium azide, purification of, 79 Sodium azidodithiocarbonate, 82 Sodium butoxide, 88 Sodium hypochlorite (solution), 90 Sodium iodate, 168 Sodium metaperiodate, 170 Sodium paraperiodate, chlorine method, 169 persulfate method, 170 Strontium amalgam, 11 Sulfur hexafluoride, 121 Sulfuryl chloride, 114... 

Strontium amalgam, 1 11 Strontium chloride, for preparation of strontium sulfide and selenide phosphors, 3 21... 

Fig. 357. Preparation of strontium amalgam. a electrolysis cell b mercuiy cathode c current lead (Pt wire) d porous clay cell e anode (graphite rod) f, g water-cooled coils.

BARIUM AMALGAM (APPLICABLE ALSO TO STRONTIUM AMALGAM)... 

Also see Barium, Cadmium, Magnesium, Potassium, Rubidium, and Strontium amalgams... 

Selective Reduction. In aqueous solution, europium(III) [22541 -18-0] reduction to europium(II) [16910-54-6] is carried out by treatment with amalgams or zinc, or by continuous electrolytic reduction. Photochemical reduction has also been proposed. When reduced to the divalent state, europium exhibits chemical properties similar to the alkaline-earth elements and can be selectively precipitated as a sulfate, for example. This process is highly selective and allows production of high purity europium fromlow europium content solutions (see Calcium compounds Strontiumand strontium compounds). 

Strontium [7440-24-6] Sr, is in Group 2 (IIA) of the Periodic Table, between calcium and barium. These three elements are called alkaline-earth metals because the chemical properties of the oxides fall between the hydroxides of alkaU metals, ie, sodium and potassium, and the oxides of earth metals, ie, magnesium, aluminum, and iron. Strontium was identified in the 1790s (1). The metal was first produced in 1808 in the form of a mercury amalgam. A few grams of the metal was produced in 1860—1861 by electrolysis of strontium chloride [10476-85-4]. 

In 1787 William Cruikshank (1745-1795) isolated, but did not identify, strontium from the mineral strontianite he examined. In 1790 Dr. Adair Crawford (1748—1794), an Irish chemist, discovered strontium by accident as he was examining barium chloride. He found a substance other than what he expected and considered it a new mineral. He named the new element strontium and its mineral strontianite after a village in Scotland. In 1808 Sir Humphry Davy treated the ore with hydrochloric acid, which produced strontium chloride. He then mixed mercury oxide with the strontium chloride to form an amalgam alloy of the two metals that collected at the cathode of his electrolysis apparatus. He heated the resulting substance to vaporize the mercury, leaving the strontium metal as a deposit. 

Strontium metal also can be prepared by thermal reduction of its oxide with aluminum. Strontium oxide-aluminum mixture is heated at high temperature in vacuum. Strontium is collected by distillation in vacuum. Strontium also is obtained by reduction of its amalgam, hydride, and other salts. The amalgam is heated and the mercury is separated by distillation. If hydride is used, it is heated at 1,000°C in vacuum for decomposition and removal of hydrogen. Such thermal reductions yield high—purity metal. 

Strontium hydride, SrH2, white solid, formed by heating strontium metal or amalgam in hydrogen gas at 250oC. Is reactive with H20, yielding strontium hydroxide and hydrogen gas. 

Copper(l)-sodium Fulminate, Na [ Cu(CNOz)] col crysts (from hot w), expl more violently than disodium salt on heating or impact. Was prepd by treating dil Na fulminate soln with cuprous chloride at 80°(Ref 1 Ref 2, pp 2754-55) Copper(l)strontium Fulminate, Sr [Cu(CN0)4]t 2HjO col microscopic crysts, expl violently on heating or on impact. Was prepd by warming Sr fulminate in w with cuprous chloride. Sr fulminate was obtd by shaking Sr amalgam with Hg fulminate in w (Ref 1 Ref 2, p 2755)... 

Cement, laboratory, 1 189 Cerite, extraction of, 2 44 Cerium, phosphor containing strontium sulfide and, 3 23 separation of, from rare earth mixtures, 2 43, 47, 48 test for, 2 50 Cerium amalgam, 1 15 Cerium-group earths, separation of, from yttrium earths by doublesulfate method, 2 44, 46 Cerium (III) magnesium nitrate, 2Ce(N03)s-3Mg(N03)2-24H,0, separation of praseodymium from lanthanum by, 2 57 Cerium(III) nitrate, 2 51 Cerium (IV) nitrate, basic, 2 49 Cesium, cesium azide for preparation of, 1 79... 

Europium, isolation of materials containing samarium, ytterbium and, by means of sodium amalgam, 5 32, 33 phosphors containing strontium sulfide or selenide and, 3 21, 22... 

Pyridinium halides are easily reduced to pyridinyl radicals (e in place of hv, eq. 1) with scKiium amalgam in oxygen-fr acetonitrile using a vacuum line and the apparatus shown in Fig. 1 After filtration, the pure pyridinyl irulicals are isolated by several distillations. Magnesium or zinc have been used on a preparative scale various other metals (e.g., calcium, strontium and barium) are suitable for preparing solutions of pyridinyl diradicals... 

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