Discovered | Name | Characteristics | Found | Reactions | Uses

Silver, a transition metal, is in Group IB [along with copper (Cu) and gold (Au)] and in the 5th period.

Silver has been known since ancient times and is mentioned in the Bible. The name comes from the Anglo-Saxon word siolfur, and the symbol from the Latin name for the element (argentum).

Although silver occurs in nature in the "native" form, it is principally found associated with ores of metals such as those of Pb, Cu, and Au. Very pure silver has a brilliant white luster, is a little harder than gold, and is only slightly less ductile and malleable than gold. It has the highest electrical and thermal conductivity of all the metals. In the solid state, the metal has a face-centered cubic structure.

Silver is usually found as the Ag(I) ion in its compounds, although AgO where Ag has an oxidation number of +2 exists. No Ag(III) salts are known. In contrast, copper commonly forms both Cu(I) and Cu(II) salts, and gold is often found as Au(I) and Au(III) compounds.

The metal is stable in pure water and air, but it tarnishes when exposed to ozone, H2S, or other sulfides. It does, however, react slowly with nitric acid.

4 Ag(s) + 6 HNO3(aq)

4 AgNO3(aq) + NO(g) + NO2(g) + 3 H2O

Extensive reaction with HCl may be prevented by the formation of insoluble AgCl on the metal's surface.

2 Ag(s) + 2 HCl(aq) AgCl(s) + H2(g)

The metal is used in the form of an alloy in silverware and coins. Sterling silver is 92.5% silver, the remainder being largely copper. Old silver coins in the U.S. were 90% Ag and 10% Cu, but, owing to the cost of silver, the metal has largely disappeared from coins worldwide. Silver is also used in batteries in miniaturized devices.

Silver metal has a germicidal effect on lower organisms, so the metal plays a dual role in dental amalgams. Such amalgams are typically 67-70% Ag, 25.3-27.7% Sn, 0-5.2% Cu, 0-1.2% Zn and some mercury.

Compounds of silver are generally made from silver nitrate (AgNO3), produced by the reaction of Ag with HNO3 (see above). The most important of these are the silver halides, AgX (where X = Cl, Br, I), which are used in photographic emulsions. About 30% of the U.S. production goes into this application. Due to the high price of silver, there is considerable interest in recovering and reusing the silver from spent film.

Finally, AgNO3 has been used for many years as a topical antiseptic. Some states still require a drop of 1% AgNO3 to be placed in each eye of newborn infants as a prophylactic against certain eye diseases.