Amalgams properties

Mercury has been known for many centuries, perhaps because its extraction is easy it has an almost unique appearance, it readily displaces gold from its ores and it forms amalgams with many other metals—all properties which caused the alchemists to regard it as one of the fundamental substances. 

Pinacol possesses the unusual property of forming a crystalline hexahydrate, m.p. 45°, and the pinacol is separated in this form from the unreacted acetone and the tsopropyl alcohol. The magnciaium is conveniently amalgamated by dissolving mercuric chloride in a portion of the acetone mercury is then liberated by the reaction ... 

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]. 

Amalgams made with spherical particles may predominate ia use over those made with flake-shaped particles because the desirable plasticity is obtained with a lower mercury content, satisfactory compaction is achieved with lower packing pressures, and there is less influence of manipulative variables upon values for appropriate physical properties. 

This, on reduction with zinc dust and acetic acid, yielded the corresponding oxime, which was further reduced by sodium amalgam to -3 4 5-trimethoxyphenylethylamine, CgHjj(OMe)3. CH. CH. NHg, and this proved to be identical with mezcaline (I). Like the latter, it behaves on analysis as if it contained the grouping —NHMe but this had already been disproved by Heffter. Interest in the remarkable physiological properties attributed to mezcaline has led to many syntheses of this alkaloid and of its isomerides and analogues. ... 

The extended ternary complex model [23] was conceived after it was clear that receptors could spontaneously activate G-proteins in the absence of agonist. It is an amalgam of the ternary complex model [12] and two-state theory that allows proteins to spontaneously exist in two conformations, each having different properties with respect to other proteins and to ligands. Thus, two receptor species are described [Ra] (active state receptor able to activate G-proteins) and [RJ (inactive state receptors). These coexist according to an allosteric constant (L = [Ra]/[Ri]) ... 

The corrosion reactions may be slowed down by using zinc alloys (with lead and cadmium, also improving the mechanical properties of zinc to simplify the production process) instead of the pure metal, or by amalgamating the inner surface of the can by adding a small amount of a mercury compound to the electrolyte. 

The properties of alloys are affected by their composition and structure. Not only is the crystalline structure important, but the size and texture of the individual grains also contribute to the properties of an alloy. Some metal alloys are one-phase homogeneous solutions. Examples are brass, bronze, and the gold coinage alloys. Other alloys are heterogeneous mixtures of different crystalline phases, such as tin-lead solder and the mercury-silver amalgams used to fill teeth. 

Data for these systems are limited. There is no evidence for the formation of intermediate phases in either the Be-Zn or the Be-Cd system in the Be-Hg system, however, the existence of BeHgj has been postulated on the basis of the properties of the amalgam formed by electrolyzing a NaCI-BeClj molten salt mixture into the Hg cathode " . 

C12-0027. Define and give an example of each of the following (a) alloy (b) amalgam (c) aerosol (d) colligative property and (e) surfactant. 

Angus, T. (1976), Cast Iron Physical and Engineering Properties, Butterworth, London. Anheuser K. (2000), Amalgam tinning of Chinese bronze antiquities, Archaeometry 42,... 

The final class of electrodes we encounter are amalgam electrodes, formed by dissolving a metal in elemental (liquid) mercury, generally to yield a solid. We denote an amalgam with brackets, so the amalgam of sodium in mercury is written as Na(Hg). The properties of such amalgams can be surprisingly different from their... 

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