Silver amalgamation

The potentiometric micro detection of all aminophenol isomers can be done by titration in two-phase chloroform-water medium (100), or by reaction with iodates or periodates, and the back-titration of excess unreacted compound using a silver amalgam and SCE electrode combination (101). Microamounts of 2-aminophenol can be detected by potentiometric titration with cupric ions using a copper-ion-selective electrode the 3- and... 

Merkur-oxyd, n. niercury oxide, specif, mercuric oxide, mercury(II) oxide, -silber, n. silver amalgam, -sulfid, n. mercury sulfide, specif, mercuric sulfide, mercury(II) sulfide. 

Catsakis, L. H. andSulica, V, I. Allergy to Silver Amalgams , Oral Surgery, Ora Medicine and Oral Pathology, 46, 371-375 (1978 ... 

Silver was formerly extracted by cyanide solution of Ag2S, the resulting Ag(CN)2 being treated with zinc to afford the metal roasted ores could also be extracted with mercury to give silver amalgam. Presently much silver is extracted by workup of the anode slime from the preparation of non-ferrous metals (Pb, Cu) pure silver is obtained by electrolysis of AgN03. 

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. 

Most substances expand when heated and contract when cooled, but liquid mercury shows an especially large variation of volume with temperature. That is why it is so often used in thermometers and barometers. Mercury also mixes with a number of metals to form alloys called amalgams. Amalgam is a special name given to alloys of mercury. With silver it forms a silver amalgam, which quickly hardens. This is the silver filling used by dentists. 

In addition to Gomberg s original method using the reaction of the triarylmethyl halide with copper, zinc, or silver amalgam in an inert solvent, a number of other methods have been used. Table II shows some of them. Some of the methods amount to oxidation of a... 

Cazo [Spanish, a copper vessel] An ancient process for extracting silver from sulfide ores. The ore was boiled in a copper pot with salt and water addition of mercury gave silver amalgam. The copper served as the reducing agent. Described in 1640 by A. A. Barba who claimed that it had been operated since 1590. Around 1800 it developed into the Fondon process, in which the raw materials were ground together. 

Washoe A process for extracting silver from sulfide ores. The ore is heated with aqueous sodium chloride in an iron pot. The chloride dissolves the silver and the iron reduces it addition of mercury gives silver amalgam ... 

While it feels as though all the mouth fills with this pain, in fact the pain only manifests itself through those teeth filled with metal, the metal being silver dissolved in mercury to form a solid - we call it a silver amalgam. Corrosion of the filling s surface causes it to bear a layer of oxidized silver, so the tooth filling also represents a redox couple, with silver and silver oxide coexisting. 

Worked Example 7.10 A tooth filling is made of a silver amalgam that comprises 37 mol% silver. What is the activity of the mercury, a(Hg) ... 

More complicated is the activity of an impure solid, e.g. a mixture of two metals (either as an alloy, or an amalgam with a metal dissolved in liquid mercury). An alloy is indicated with a colon, so a nickel-silver alloy is written as Ni Ag. An amalgam is indicated with the mercury in brackets, so a silver amalgam is written as Ag(Hg). Consider an alloy of cobalt (90 mol%) and silver (10 mol%) there will be two activities in such a system, i.e. one each for silver and cobalt in the Co Ag alloy. The activity in such a situation is merely the mole fraction x, so aco = 0.9, and a g = 0.1. 

Elemental mercury is used industrially in electric lamps and switches, gauges and controls (e.g. thermometers, barometers, thermostats), battery production, nuclear weapons production, and the specialty chemical industry, including the production of caustic soda. Because elemental mercury has a high affinity for gold and silver, it has been, and continues to be, used in precious metal extraction from ore. Elemental mercury has been used for over one hundred years in mercury-silver amalgam preparations to repair dental caries. Mercury continues to be used in folk remedies and in certain cultural practices, with unknown public health implications. 

The most common oral condition and dental emergency is dental caries, which is a destructive disease of the hard tissues of the teeth due to bacterial infection with Streptococcus mutans and other bacteria. It is characterized by destruction of enamel and dentine. Dental decay presents as opaque white areas of enamel with grey undertones and in more advanced cases, brownish discoloured cavitations. Dental caries is initially asymptomatic and pain does not occur until the decay impinges on the pulp, and an inflammation develops. Treatment of caries involves removal of the softened and infected hard tissues, sealing of exposed dentines and restoration of the lost tooth structure with porcelain, silver, amalgam, composite plastic, gold etc. 

Six pounds of mercury and silver amalgamated, heated in four different vessels for eight days showed an increase of weight of three pounds. This augmentation comes from the union of a spirit with the metallic body (spiritus unitur corpori).12... 

The formation of silver amalgam is described by dissolving silver in aqua fortis and then ... 

There is here a touch of alchemical pretention, in the interpretation of the result of this experiment, which may give a solid silver amalgam, hut does not solidify the entire mass of quicksilver, when used in these proportions. 

A naturally occurring alloy of silver with mercuiy, also referred to as mercurian silver, silver amalgam, and argental mercuiy. The natural amalgam crystallizes in the isometric system hardness. 3-3.5 sp gr, 13.75-14.1 luster, metallic, color, silver-white streak, silver-white opaque, Amalgam is found in Bavaria. British Columbia. Chile, the Czech Republic and Slovakia, France, Norway, and Spain. In some areas, it is found in the oxidation zone of silver deposits and as scattered grains in cinnabar ores. 

Ag3Hg4 (c). Data on the silver amalgams were reported by Berthe-lot123 and Littleton.1... 

Catsakis LH, Sulica VI. 1978. Allergy to silver amalgams. Oral Surg 46 371-375. 

Huggins HA. 1983. Mercury-a factor in mental disease Part 1. Can mercury-silver amalgams cause psychiatric symptoms. Oral Health 73 42-45. 

Moller B. 1979. Reactions of human dental pulp to silver amalgam restorations. A study with emphasis on source material characteristics. Swedish Dent [Suppl] 2 1-37. 

Raskin RB. 1984. Toxicity of silver amalgam Fact or fiction. NY State Dent J 50 582, 585, 587. 

Strassburg M, Schubel F. 1967. [Generalized allergic reaction caused by silver amalgam fillings], Deutsch Zahnarztuche Zeitschrift 22 3-9. (German). 

Solutions aren t necessarily liquids. Air is a solution of nitrogen, oxygen, and a few other minor gases. Mixtures of oxygen and nitrous oxide are also solutions. Dental fillings used to be made of silver amalgams, which are solid solutions of silver and mercury. 

Another process for preparing hydrogen peroxide directly from dilute sulphuric acid is the subject of two patents.4 Electrolysis is conducted under high pressure inside steel cylinders, each of which is lined with a suitable cathode material, e.g. silver amalgam or copper amalgam. 

The - electrochemical window of polished solid silver amalgam electrode (p-AgSAE) as for an electrode which does not contain liquid mercury is exceptionally broad. This fact allows the application of p-MeSAE for determination of species at rather negative potentials. An important advantage is that the electrodes from solid amalgams of different metals can be prepared in a relatively simple way, and that in their applications specific interactions between these metals and the studied compounds can be utilized. 

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