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Silver ( Anglo-Saxon, Seolfor siolfur; Ag is from the Latin argentum) has been known since ancient times. It is mentioned in the book of Genesis and slag heaps found in Asia Minor and on the islands of the Aegean Sea indicate that silver was being separated from lead as early as the 4th millennium BC.
Silver has been used for thousands of years as ornaments and utensils, for trade, and as the basis for many monetary systems. It was long considered the second most precious metal, second only to gold.
Associated with the moon, as well as with the sea and various lunar goddesses, the metal was referred to by alchemists by the name luna. One of the alchemical symbols for silver is a crescent moon with the open part on the left (see picture, right).
The metal mercury was thought of as a kind of silver, though the two elements are chemically unrelated; its names hydrargyrum ("watery silver") and the English quicksilver attest to this.
In heraldry, the argent, in addition to being shown as silver (this has been shown at times with real silver in official representations), can also been shown as white. Occasionally, the word "silver" is used rather than argent; sometimes this is done across-the-board, sometimes to avoid repetition of the word "argent" in blazon.
Europeans found huge amount of silver in the New World in Zacatecas, Mexico and Potosí, which triggered a period of inflation in Europe.
The Rio de la Plata was named after silver (in Spanish, plata), and in turn lent the meaning of its name to Argentina.
Silver is found in native form, combined with sulfur, arsenic, antimony, or chlorine and in various ores such as argentite (Ag2 S) and horn silver (Ag Cl). The principal sources of silver are copper, copper- nickel, gold, lead and lead- zinc ores obtained from Canada, Mexico, Peru, Australia and the United States.
This metal is also produced during the electrolytic refining of copper. Commercial grade fine silver is at least 99.9% pure silver and purities greater than 99.999% are available. Mexico is the largest silver producer. According to the Secretary of Economics of Mexico, it produced 2747 tons in 2000, about 15% of the annual production of the world.
Naturally occurring silver is composed of the two stable isotopes Ag-107 and Ag-109 with Ag-107 being the most abundant (51.839% natural abundance). Twenty-eight radioisotopes have been characterized with the most stable being Ag-105 with a half-life of 41.29 days, Ag-111 with a half-life of 7.45 days, and Ag-112 with a half-life of 3.13 hours. All of the remaining radioactive isotopes have half-lifes that are less than an hour and the majority of these have half lifes that are less than 3 minutes. This element also has numerous meta states with the most stable being Agm-128 (t* 418 years), Agm-110 (t* 249.79 days) and Agm-107 (t* 8.28 days).
Isotopes of silver range in atomic weight from 93.943 amu (Ag-94) to 123.929 amu (Ag-124). The primary decay mode before the most abundant stable isotope, Ag-107, is electron capture and the primary mode after is beta decay. The primary decay products before Ag-107 are palladium (element 46) isotopes and the primary products after are cadmium (element 48) isotopes.
The palladium isotope Pd-107 decays by beta emission to Ag-107 with a half-life of 6.5 million years. Iron meteorites are the only objects with a high enough Pd/Ag ratio to yield measurable variations in Ag-107 abundance. Radiogenic Ag-107 was first discovered in the Santa Clara meteorite in 1978. The discoverers suggest that the coalescence and differentiation of iron-cored small planets may have occurred 10 million years after a nucleosynthetic event. Pd-107 versus Ag correlations observed in bodies, which have clearly been melted since the accretion of the solar system, must reflect the presence of live short-lived nuclides in the early solar system.
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