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7440-22-4

7440-22-4 Structure

7440-22-4 Structure
IdentificationMore
[Name]

Silver
[CAS]

7440-22-4
[EINECS(EC#)]

231-131-3
[Molecular Formula]

Ag
[MDL Number]

MFCD00003397
[Molecular Weight]

107.87
[MOL File]

7440-22-4.mol
Chemical PropertiesBack Directory
[Definition]

Metallic element, atomic number 47, group IB of the periodic table, aw 107.868, valence of 1, two stable isotopes.
[Appearance]

Silver is a white lustrous metal that is extremely ductile and malleable.
[Appearance]

lustrous soft white metal
[mp ]

960 °C(lit.)
[bp ]

2212 °C(lit.)
[density ]

1.135 g/mL at 25 °C
[vapor density ]

5.8 (vs air)
[vapor pressure ]

0.05 ( 20 °C)
[refractive index ]

n20/D 1.333
[Fp ]

232 °F
[storage temp. ]

2-8°C
[solubility ]

H2O: soluble
[form ]

wool
[Stability:]

Stable. Substances to be avoided include strong acids and strong bases, tartaric acid, oxalic acid. Blackened by contact with ozone, hydrogen sulfide, sulfur. Powder is highly flammable.
[Water Solubility ]

insoluble
[Merck ]

13,8577
[History]

Slag dumps in Asia Minor and on islands in the Aegean Sea indicate that man learned to separate silver from lead as early as 3000 B.C. Silver occurs native and in ores such as argentite (Ag2S) and horn silver (AgCl); lead, lead-zinc, copper, gold, and copper-nickel ores are principal sources. Mexico, Canada, Peru, and the U.S. are the principal silver producers in the western hemisphere. Silver is also recovered during electrolytic refining of copper. Commercial fine silver contains at least 99.9% silver. Purities of 99.999+% are available commercially. Pure silver has a brilliant white metallic luster. It is a little harder than gold and is very ductile and malleable, being exceeded only by gold and perhaps palladium. Pure silver has the highest electrical and thermal conductivity of all metals, and possesses the lowest contact resistance. It is stable in pure air and water, but tarnishes when exposed to ozone, hydrogen sulfide, or air containing sulfur. The alloys of silver are important. Sterling silver is used for jewelry, silverware, etc. where appearance is paramount. This alloy contains 92.5% silver, the remainder being copper or some other metal. Silver is of utmost importance in photography, about 30% of the U.S. industrial consumption going into this application. It is used for dental alloys. Silver is used in making solder and brazing alloys, electrical contacts, and high capacity silver–zinc and silver–cadmium batteries. Silver paints are used for making printed circuits. It is used in mirror production and may be deposited on glass or metals by chemical deposition, electrodeposition, or by evaporation. When freshly deposited, it is the best reflector of visible light known, but is rapidly tarnishes and loses much of its reflectance. It is a poor reflector of ultraviolet. Silver fulminate (Ag2C2N2O2), a powerful explosive, is sometimes formed during the silvering process. Silver iodide is used in seeding clouds to produce rain. Silver chloride has interesting optical properties as it can be made transparent; it also is a cement for glass. Silver nitrate, or lunar caustic, the most important silver compound, is used extensively in photography. While silver itself is not considered to be toxic, most of its salts are poisonous. Natural silver contains two stable isotopes. Fifty-six other radioactive isotopes and isomers are known. Silver compounds can be absorbed in the circulatory system and reduced silver deposited in the various tissues of the body. A condition, known as argyria, results with a greyish pigmentation of the skin and mucous membranes. Silver has germicidal effects and kills many lower organisms effectively without harm to higher animals. Silver for centuries has been used traditionally for coinage by many countries of the world. In recent times, however, consumption of silver has at times greatly exceeded the output. In 1939, the price of silver was fixed by the U.S. Treasury at 71¢/troy oz., and at 90.5¢/troy oz. in 1946. In November 1961 the U.S. Treasury suspended sales of nonmonetized silver, and the price stabilized for a time at about $1.29, the melt-down value of silver U.S. coins. The Coinage Act of 1965 authorized a change in the metallic composition of the three U.S. subsidiary denominations to clad or composite type coins. This was the first change in U.S. coinage since the monetary system was established in 1792. Clad dimes and quarters are made of an outer layer of 75% Cu and 25% Ni bonded to a central core of pure Cu. The composition of the oneand five-cent pieces remains unchanged. One-cent coins are 95% Cu and 5% Zn. Five-cent coins are 75% Cu and 25% Ni. Old silver dollars are 90% Ag and 10% Cu. Earlier subsidiary coins of 90% Ag and 10% Cu officially were to circulate alongside the clad coins; however, in practice they have largely disappeared (Gresham’s Law), as the value of the silver is now greater than their exchange value. Silver coins of other countries have largely been replaced with coins made of other metals. On June 24, 1968, the U.S. Government ceased to redeem U.S. Silver Certificates with silver. Since that time, the price of silver has fluctuated widely. As of January 2002, the price of silver was about $4.10/troy oz. (13¢/g); however the price has fluctuated considerably due to market instability. The price of silver in 2001 was only about four times the cost of the metal about 150 years ago. This has largely been caused by Central Banks disposing of some of their silver reserves and the development of more productive mines with better refining methods. Also, silver has been displaced by other metals or processes, such as digital photography.
[Uses]

silver can provide color to a product or serve as a deodorant. This metal is a good example of when nanotechnology may be used to increase an ingredient’s compatibility with a cosmetic formulation, and in this form may be also used as a preservative.
[Uses]

This malleable white metal is found as argentite (Ag2S) and horn silver (AgCl) or in lead and copper ore. Copper plates coated with a thin layer of elemental silver and fumed with iodine were used by Niépce and Daguerre. Aside from the heliograph and physautotype, silver halide compounds were the basis of all photographic processes used in the camera and most of the printing processes during the 19th century.
[CAS DataBase Reference]

7440-22-4(CAS DataBase Reference)
[NIST Chemistry Reference]

Silver(7440-22-4)
[EPA Substance Registry System]

7440-22-4(EPA Substance)
Safety DataBack Directory
[Hazard Codes ]

N,Xn,T
[Risk Statements ]

R22:Harmful if swallowed.
R38:Irritating to the skin.
R20/21:Harmful by inhalation and in contact with skin .
R10:Flammable.
R40:Limited evidence of a carcinogenic effect.
R34:Causes burns.
R23/24/25:Toxic by inhalation, in contact with skin and if swallowed .
[Safety Statements ]

S26:In case of contact with eyes, rinse immediately with plenty of water and seek medical advice .
S24/25:Avoid contact with skin and eyes .
S25:Avoid contact with eyes .
S45:In case of accident or if you feel unwell, seek medical advice immediately (show label where possible) .
S36/37/39:Wear suitable protective clothing, gloves and eye/face protection .
S23:Do not breathe gas/fumes/vapor/spray (appropriate wording to be specified by the manufacturer) .
[RIDADR ]

UN 3264 8/PG 3
[WGK Germany ]

3
[RTECS ]

VW3500000
[F ]

8
[HazardClass ]

6.1
[PackingGroup ]

III
[HS Code ]

71069110
[Safety Profile]

Human systemic effects by inhalation: skin effects. Inhalation of dusts can cause argyrosis. Questionable carcinogen with experimental tumorigenic data. Flammable in the form of dust when exposed to flame or by chemical reaction with C2H2, NH3, bromoazide, ClF3 ethyleneimine, H2O2, oxalic acid, H2SO4, tartaric acid. Incompatible with acetylene, acetylene compounds, aziridine, bromine azide, 3-bromopropyne, carboxylic acids, copper + ethylene glycol, electrolytes + zinc, ethanol + nitric acid, ethylene oxide, ethyl hydroperoxide, ethyleneimine, iodoform, nitric acid, ozonides, peroxomonosulfuric acid, peroxyformic acid. See also POWDERED METALS and SILVER COMPOUNDS.
[Hazardous Substances Data]

7440-22-4(Hazardous Substances Data)
Raw materials And Preparation ProductsBack Directory
[Preparation Products]

Formaldehyde-->Alkyd resin paint-->Silver nitrate-->Silver oxide-->Silver sulfate-->Silver chloride-->DAD-40 conductive adhesive-->zinc-silver storage battery-->DAD-6 conductive adhesive-->DAD-24 adhesive-->DAD-54 conductive adhesive-->Silver carbonate
Hazard InformationBack Directory
[General Description]

SILVER(7440-22-4)y metallic solid.
[Reactivity Profile]

SILVER reacts violently with chlorine trifluoride (in the presence of carbon) [Mellor 2 Supp. 1 1956]. Bromoazide explodes on contact with silver foil. Acetylene forms an insoluble acetylide with silver [Von Schwartz 1918 p. 142 ]. When silver is treated with nitric acid in the presence of ethyl alcohol, silver fulminate, which can detonated may be formed. Ethyleneimine forms explosive compounds with silver, hence silver solder should not be used to fabricate equipment for handling ethyleneimine. Finely divided silver and strong solutions of hydrogen peroxide may explode [Mellor 1:936 1946-47)]. Incompatible with oxalic acid and tartaric acid [Nav Aer. 09-01-505 1956]. Silver can form explosive salts with azidrine. ("Ethyleneimine" Brocure 125-521-65, Midland (Mich.), Dow Chemical Co., 1965). Ammonia forms explosive compounds with gold, mercury, or silver. (Eggeman, Tim. "Ammonia" Kirk-Othmer Encyclopedia of Chemical Technology. John Wiley & Sons, Inc. 2001.). Acetylene and ammonia can form explosive silver salts in contact with Ag. (Renner, Hermann, Gunther Schlamp. “Silver, Silver Compounds, and Silver Alloys." Ullmann's Encyclopedia of Industrial Chemistry. Wiley-VCH Verlag GmbH & Co. KGaA. 2001.)
[Air & Water Reactions]

Insoluble in water.
[Hazard]

Toxic material.
[Potential Exposure]

Silver may be alloyed with copper, aluminum, cadmium, lead, or antimony. The alloys are used in the manufacture of silverware, jewelry, coins, ornaments, plates, commutators, scientific instruments; automobile bearing; and grids in storage batteries. Silver is used in chromenickel steels, in solders and brazing alloys; in the application of metallic films on glass and ceramics, to increase corrosion resistance to sulfuric acid, in photographic films, plates and paper; as an electroplated undercoating for nickel and chrome; as a bactericide for sterilizing water; fruit juices; vinegar, etc.; in bus bars and windings in electrical plants; in dental amalgams; and as a chemical catalyst in the synthesis of aldehydes. Because of its resistance to acetic and other food acids, it is utilized in the manufacture of pipes, valves, vats, pasteurizing coils and nozzles for the milk, vinegar, cider, brewing, and acetate rayon silk industries.
[First aid]

If this chemical gets into the eyes, remove any contact lenses at once and irrigate immediately for at least 15 minutes, occasionally lifting upper and lower lids. Seek medical attention immediately. If this chemical contacts the skin, remove contaminated clothing and wash immediately with soap and water. Seek medical attention immediately. If this chemical has been inhaled, remove from exposure, begin rescue breathing (using universal precautions, including resuscitation mask) if breathing has stopped and CPR if heart action has stopped. Transfer promptly to a medical facility. When this chemical has been swallowed, get medical attention. Give large quantities of water and induce vomiting. Do not make an unconscious person vomit.
[Fire Hazard]

Dust is flammable.
[Incompatibilities]

Dust may form explosive mixture with air. Powders are incompatible with strong oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides May react and/or form dangerous or explosive compounds, with acetylene, ammonia, halogens, hydrogen peroxide; bromoazide, concentrated or strong acids, oxalic acid, tartaric acid, chlorine trifluoride, ethyleneimine.
[Waste Disposal]

Recovery, wherever possible, in view of economic value of silver. Techniques for silver recovery from photoprocessing and electroplating wastewaters have been developed and patented.
Material Safety Data Sheet(MSDS)Back Directory
[msds information]

C.I. 77820(7440-22-4).msds
Questions And AnswerBack Directory
[History]

Silver is one of the oldest metals, known since ancient times. It is a precious metal worldwide, used in ornaments, coins, and utensils. The symbol Ag for this element is derived from the Latin word, argentum. Silver occurs in nature in native form, commonly associated with gold. It is found in most lead and copper ores. The principal mineral of silver is argentite, Ag2S [1332-04-3]. Some other silver minerals include pyrargyrite, Ag3SbS3 [15123-77-0]; proustite, Ag3AsS3 [15152-58-4]; polybasite, Ag16Sb2S11 [53810-31-4]; cerargyrite, AgCl [14358-96-4]; stephanite, Ag5SbS4 [1302-12-1]; and tetrahedrite, Cu3(AsSb)S3. Abundance of silver in the earth’s crust is estimated to be 0.075 mg/kg and its average concentration in sea water is 0.014 µg/L.
[Uses]

Silver and its alloys and compounds have numerous applications. As a precious metal, silver is used in jewelry. Also, one of its alloys, sterling silver, containing 92.5 weight % silver and 7.5 weight % copper, is a jewelry item and is used in tableware and decorative pieces. The metal and its copper alloys are used in coins. Silver-copper brazing alloys and solders have many applications. They are used in automotive radiators, heat exchangers, electrical contacts, steam tubes, coins, and musical instruments.
Some other uses of silver metal include its applications as electrodes, catalysts, mirrors, and dental amalgam. Silver is used as a catalyst in oxidation-reductions involving conversions of alcohol to aldehydes, ethylene to ethylene oxide, and ethylene glycol to glyoxal.
[Production Methods]

Many processes are known for recovery of silver from its ores. These depend mostly on the nature of the mineral, its silver content, and recovery of other metals present in the ore. A few processes are briefly outlined below.
Silver is usually extracted from high-grade ores by three common processes that have been known for many years. These are amalgamation, leaching, and cyanidation. In one amalgamation process, ore is crushed and mixed with sodium chloride, copper sulfate, sulfuric acid, and mercury, and roasted in cast iron pots. The amalgam is separated and washed. Silver is separated from its amalgam by distillation of mercury.
In the cyanidation process the ore is crushed and roasted with sodium chloride and then treated with a solution of sodium cyanide. Silver forms a stable silver cyanide complex, [Ag(CN)2]–. Adding metallic zinc to this complex solution precipitates silver. Several leaching processes are known. One such process, known as the Patera process, developed in the mid 19th century, involves roasting ore with sodium chloride followed by leaching with sodium thiosulfate solution. Silver 834 SILVERis precipitated as silver sulfide, Ag2S, by adding sodium sulfide to the leachate. In the Clandot process, leaching is done with ferric chloride solution. Addition of zinc iodide precipitates silver iodide, AgI. AgI is reduced with zinc to obtain silver.
The above processes are applied for extraction of silver from high-grade ores. However, with depletion of these ores, many processes were developed subsequently to extract silver from low-grade ores, especially lead, copper, and zinc ores that contain very small quantities of silver.
Low grade ores are concentrated by floatation. The concentrates are fed into smelters (copper, lead, and zinc smelters). The concentrates are subjected to various treatments before and after smelting including sintering, calcination, and leaching. Copper concentrates are calcined for removal of sulfur and smelted in a reverberatory furnace to convert into blister copper containing 99 wt% Cu. The blister copper is fire-refined and cast into anodes. The anodes are electrolytically refined in the presence of cathodes containing 99.9% copper. Insoluble anode sludges from electrolytic refining contain silver, gold, and platinum metals. Silver is recovered from the mud by treatment with sulfuric acid. Base metals dissolve in sulfuric acid leaving silver mixed with any gold present in the mud. Silver is separated from gold by electrolysis.
Lead and zinc concentrates can be treated in more or less the same manner as copper concentrates. Sintering lead concentrates removes sulfur and following that smelting with coke and flux in a blast furnace forms impure lead bullion. The lead bullion is drossed with air and sulfur and softened with molten bullion in the presence of air to remove most impurities other than silver and gold. Copper is recovered from the dross and zinc converts to its oxide and is recovered from blast furnace slag. The softened lead obtained above also contains some silver. The silver is recovered by the Parkes Process. The Parkes process involves adding zinc to molten lead to dissolve silver at temperatures above the melting point of zinc. On cooling, zinc-silver alloy solidifies, separating from the lead and rising to the top. The alloy is lifted off and zinc is separated from silver by distillation leaving behind metallic silver.
The unsoftened lead obtained after the softening operation contains silver in small but significant quantities. Such unsoftened lead is cast into anode and subjected to electrolytic refining. The anode mud that is formed adhering to these anodes is removed by scraping. It contains bismuth, silver, gold, and other impurity metals. Silver is obtained from this anode mud by methods similar to the extraction of anode mud from the copper refining process discussed earlier.
If the low–grade ore is a zinc mineral, then zinc concentrate obtained from the flotation process is calcined and leached with water to remove zinc. Silver and lead are left in leach residues. Residues are treated like lead concentrates and fed into lead smelters. Silver is recovered from this lead concentrate by various processes described above.
Well-known Reagent Company Product InformationBack Directory
[Acros Organics]

Silver, shot, 99.9999%, 1-3 mm (1ea = 5gr)(7440-22-4)
[Alfa Aesar]

Silver wool, 99.9+% (metals basis)(7440-22-4)
[Sigma Aldrich]

7440-22-4(sigmaaldrich)
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