Silver, Mercury (element)
, Silver Surfer
, Silver Star
, Silver age
, Silver Jubilee
, Colloidal silver
, Tactical frivolity
, Forgotten Silver
: ) is a chemical element
with the symbol Ag
). A soft white lustrous transition metal
, it has the highest electrical and thermal conductivity of any metal and occurs in mineral
s and in free form. This metal is used in coin
, and in mirrors.
Notable characteristicsleft|thumb|A nugget of silver
Silver is a very ductile and malleable (slightly harder than gold
) univalent coinage metal
with a brilliant white metallic luster that can take a high degree of polish
. It has the highest electrical conductivity
of all metals, even higher than copper
, but its greater cost and tarnishability has prevented it from being widely used in place of copper for electrical purposes.
Pure silver also has the highest thermal conductivity
, whitest color, the highest optical reflectivity
(although it is a poor reflector of ultraviolet
light), and the lowest contact resistance of any metal. Silver halides are photosensitive and are remarkable for the effect of light upon them. This metal is stable in pure air and water, but does tarnish when it is exposed to ozone
, hydrogen sulfide
, or air containing sulfur
. The most common oxidation state
of silver is +1 (for example, silver nitrate
); a few +2 (for example, silver(II) fluoride
) and +3 compounds (for example, silver(III) persulfate
) are also known.
The principal use of silver is as a precious metal
. Its salts, especially silver nitrate
and silver halides
, are also widely used in photography (which is the largest single end use of silver).
Some other uses for silver are as follows:
*Electrical and electronic products, which need silver's superior conductivity, even when tarnished. For example, printed circuits are made using silver paints, and computer keyboards use silver electrical contacts. Silver (silver cadmium oxide) is also used in high voltage contacts because it can minimize any arcing
s which need superior reflectivity for visible light are made with silver as the reflecting material in a process called silvering
. Common mirrors are backed with aluminium
*Many high end musical instruments
are made with silver, which benefit from a higher tone quality.
*Silver has been coined to produce money since 700 BC
by the Lydia
ns, in the form of electrum
. Later, silver was refined and coined in its pure form. The words for "silver" and "money" are the same in at least 14 languages.
*The metal is chosen for its beauty in the manufacture of jewelry and silverware, which are traditionally made from the silver alloy known as Sterling silver
, which is 92.5% silver and usually alloyed with copper. The name of United Kingdom monetary unit 'Pound' originally had the value of one troy pound of sterling silver.
*Silver is also used in medals, denoting second place.
*The malleability, non-toxicity and beauty of silver make it useful in dental alloys for fittings and fillings.
*Silver's catalytic properties make it ideal for use as a catalyst
in oxidation reactions; for example, the production of formaldehyde
and air by means of silver screens or crystallite
s containing a minimum 99.95 weight
-percent silver. Silver (upon some suitable support) is probably the only catalyst available today to convert ethylene
to ethylene oxide
(later hydrolyzed to ethylene glycol
, used for making polyester
s)—a very important industrial reaction.
dissolves in silver relatively easily compared to other gases present in air. Attempts have been made to construct silver membrane
s of only a few monolayer
s thickness. Such a membrane could be used to filter pure oxygen from air.
*Used to make solder
and brazing alloys, electrical contact
s, and high capacity silver-zinc
and silver-cadmium batteries
, also known as Silver Whiskers
, is formed when silver electrical contact
s are used in an atmosphere rich in hydrogen sulfide
is a powerful explosive
can be made transparent and is used as a cement
is also a widely used electrode for pH
testing and potentiometric
has been used in attempts to seed cloud
s to produce rain.
is used as a positive electrode (cathode
) in watch batteries.
is a possible antibacterial / antibiotic treatment espoused in alternative medicine, also notorious for causing argyria
(liquid) was a standard of care but was largely replaced by silver sulfadiazine
cream (SSD Cream) which was generally the "standard of care" for the antibacterial/antibiotic treatment of serious burns until the late 1990's. Now, other options such as silver coated dressings (activated silver dressings) are used in addition to SSD cream, and may present advantages such as pain reduction and capacity for treatment at home.
*Silver is often used in modern horror fiction
as a weapon against certain supernatural
entities, especially werewolves
, who are sometimes described as being burned by silver.
Historyleft|thumb|75px|Alchemical symbol for silver
Silver (from Anglo-Saxon seolfor
, compare Old High German silabar
; 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 for ornament
s and utensil
s, for trade
, and as the basis for many monetary system
s. Its value as a precious metal
was long considered second only to gold
. In Ancient Egypt
and Medieval Europe
, it was often more valuable than gold.Judas Iscariot
is infamous for having, according to the New Testament
, taken a bribe of thirty pieces of silver from religious leaders in Jerusalem
to turn Jesus Christ
over to the Romans.
Associated with the moon
, as well as with the sea and various lunar goddess
es, 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, left).
The metal mercury
was thought of as a kind of silver, though the two elements are chemically unrelated; its Latin and English
("watery silver") and quicksilver,
respectively, reflect this history.
, the argent
, in addition to being shown as silver (this has been shown at times with real silver in official representations), can also be 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 a huge amount of silver in the New World
, which triggered a period of inflation in Europe. The conquistador Pizarro
was said to have resorted to having his horses shod with silver horseshoes due to the metal's abundance, in contrast to the relative lack of iron in Peru
. Silver, which was extremely valuable in China
, became a global commodity, contributing to the rise of the Spanish
Empire. The rise and fall of its value affected the world market.
The Rio de la Plata
was named after silver (in Spanish
), and in turn lent the meaning of its name to Argentina
Silver mining was a driving force in the settlement of western North America, with major booms for silver and associated minerals (primarily lead) in the galena ore silver is most commonly found in. Notable "silver rushes"
were in Colorado
, Cobalt, Ontario
and the Kootenay
region of British Columbia, notably in the Boundary
and "Silvery Slocan"
. The largest silver ore deposits in the United States were discovered at the Comstock Lode
in Virginia City, Nevada, in 1859.
Occurrence and extractionthumb|left|Silver ore (Lincoln cent is shown for scale)
Silver is found in native form, combined with sulfur
, or chlorine
and in various ores such as argentite
) and horn silver
The principal sources of silver are copper
ores obtained from Canada
, Cobalt, Ontario
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 world's largest silver producer. According to the Secretary of Economics of Mexico, it produced 80,120,000 troy ounce
s (2492 metric ton
s) in 2000, about 15% of the annual production of the world.
silver bullion bar]
main|Silver as an investment|Silver
Silver is currently about 1/50th the price of gold by mass, and approximately 70 times more valuable than copper
. Silver did once trade at 1/6th to 1/12th the price of gold, prior to the Age of Discovery
and the discovery of great silver deposits in the Americas, most notably the vast Comstock Lode
in Virginia City
, USA. This then resulted in the debate over cheap Free Silver
to benefit the agricultural sector was among the most prolongued and difficult in that country's history and dominated public discourse during the latter decades of the nineteenth century.
Over the last 100 years the price of silver and the gold/silver price ratio has fluctuated greatly due to competing industrial and store of value
demands. In 1980 the silver price rose to an all-time high of US$49.45 per troy ounce
. By December 2001 the price had fallen to US$4.15 per ounce, and in May 2006 it had risen back as high as US$15.21 per ounce. As of 2006
, current silver prices (and most other metal prices) have been rather volatile, for example quickly dropping from the May high of US$15.21 per ounce to a June low of US$9.60 per ounce before rising back above US$12 per ounce by August.
[cite web | url=http://charts3.barchart.com/chart.asp?sym=SIY0&data=A&jav=adv&vol=Y&evnt=adv&grid=Y&code=BSTK&org=stk&fix=|publisher=Barchart.com | title=Silver Cash daily ]
Naturally occurring silver is composed of the two stable isotope
Ag and 109
Ag with 107
Ag being the more abundant (51.839% natural abundance
). Twenty-eight radioisotope
s have been characterised with the most stable being 105
Ag with a half-life
of 41.29 days, 111
Ag with a half-life of 7.45 days, and 112
Ag 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 state
s with the most stable being 108m
418 years), 110m
249.79 days) and 106m
Isotopes of silver range in atomic weight
from 93.943 u
Ag) to 123.929 u (124
Ag). The primary decay mode
before the most abundant stable isotope, 107
Ag, is electron capture
and the primary mode after is beta decay
. The primary decay product
s before 107
Ag are palladium
(element 46) isotopes and the primary products after are cadmium
(element 48) isotopes.
The palladium isotope 107
Pd decays by beta emission to 107
Ag with a half-life of 6.5 million years. Iron meteorite
s are the only objects with a high enough Pd
/Ag ratio to yield measurable variations in 107
Ag abundance. Radiogenic 107
Ag was first discovered in the Santa Clara
meteorite in 1978
The discoverers suggest that the coalescence and differentiation of iron-cored small planet
s may have occurred 10 million years after a nucleosynthetic
Pd 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.
, the father of modern medicine, wrote that silver had beneficial healing and anti-disease properties, and the Phoenicians used to store water, wine, and vinegar in silver bottles to prevent spoiling. In the early 1900s people would put silver dollar
s in milk bottles to prolong the milk's freshness. Silver compounds were used successfully to prevent infection in World War I
before the advent of antibiotic
The widespread use of silver went out of fashion with the development of modern antibiotics. However, recently there has been renewed interest in silver as a broad spectrum antimicrobial. In particular, it is being used with alginate, a naturally occurring biopolymer
derived from seaweed, in a range of silver alginate
products designed to prevent infections as part of wound
management procedures, particularly applicable to burn
victims. In addition, Samsung has introduced washing machines with a final rinse containing silver ions to provide several days of antibacterial protection in the clothes.
[cite web | title=Samsung laundry featuring SilverCare Technology | publisher=Samsung | url=http://www.samsung.com/PressCenter/PressRelease/PressRelease.asp?seq=20060213_0000233684 | accessdate=2006-05-20 ]
Additionally, Kohler has introduced a line of toilets that have silver ions embedded in the porcelain to kill germs.
Silver plays no known natural biological role in humans, and possible health effects of silver are a subject of dispute. Silver itself is not toxic but most silver salts
are, and some may be carcinogenic
Silver and compounds containing silver (like colloidal silver
) can be absorbed into the circulatory system
and become deposited in various body tissues leading to a condition called argyria
which results in a blue-grayish pigmentation of the skin, eyes, and mucous membrane
s. Although this condition does not harm a person's health, it is disfiguring and usually permanent. Argyria is rare and mild forms are sometimes mistaken for cyanosis
Silver-ions and silver compounds show a toxic effect on some bacteria, viruses, algae and fungi typical for heavy metals like lead
, but without the high toxicity to humans that is normally associated with them. Its germicidal effects kills many microbial organisms in vitro
(i.e. in a test tube
or a petri dish
). The exact process by which this is done is still not well understood, although several different theories exist. One of these is a process generally known for heavy metals called the oligodynamic effect
, which goes a long way explaining the effect on microbial lifeforms but does not explain certain antiviral functions.
Today, various kinds of silver compounds, or devices to make solutions or colloids
containing silver, are sold as remedies for a wide variety of diseases. Although mostly harmless, some people using these home-made solutions use far too much and develop argyria
over a period of months or years, and several have been documented in the last few years in the medical literature, including one possible case of coma associated with a high intake of silver (see medical references). It is strongly advised to notify a doctor when taking silver as a form of self-medication.
In India, foods can be found decorated with a thin layer of silver, known as Varak
. Silver as a food additive is given the E number
E174 and classed as a food coloring
. It is used solely for external decoration, such as on chocolate
confectionery, in the covering of dragées
and the decoration of sugar-coated flour confectionery. In Australia
, it is banned as a food additive.
Because of the mysticism surrounding silver's lunar
associations, as well as the aesthetic qualities of the white, reflective metal that cause it to be associated with purity, silver in European Folklore
has long been traditionally believed to be an antidote to various maladies and fictional monsters
. Notably, silver was believed to be a repellant against vampire
s (this primarily originates from its holy connotations; also, mirrors were originally polished silver, and as such, vampires allegedly cannot be seen in them because they are wicked) and it was believed that a werewolf
, in his bestial form, could only be killed by a weapon or bullet made of silver, and was equally effective against vampires, as described in Eastern European folklore. This has given rise to the term "silver bullet
," which is used to describe things that very effectively deal with one specific problem.
*http://periodic.lanl.gov/elements/47.html Los Alamos National Laboratory – Silver
*Silver as an investment
*http://www.webelements.com/webelements/elements/text/Ag/index.html WebElements.com – Silver
*http://minerals.usgs.gov/minerals/pubs/commodity/silver/ Silver Statistics and Information
publications on the worldwide production of silver
*http://www.silverinstitute.org The Silver Institute
A silver industry website
*http://www.theodoregray.com/PeriodicTable/Elements/047/index.html A collection of silver items
Samples of silver
Publications on health effects
*http://dermatology.cdlib.org/111/case_reports/argyria/wadhera.html Systemic argyria associated with ingestion of colloidal silver
*http://www.neurology.org/cgi/content/full/62/8/1408 Myoclonic status epilepticus following repeated oral ingestion of colloidal silver
*http://www.pubmedcentral.gov/articlerender.fcgi?tool=pubmed&pubmedid=185946 Specific Inactivation of Herpes Simplex Virus by Silver Nitrate at Low Concentrations and Biological Activities of the Inactivated Virus
*http://www.pubmedcentral.gov/pagerender.fcgi?artid=429446&pageindex=1 Prevention of Herpes Keratoconjunctivitis in Rabbits By Silver SulfadiazineCategory:Chemical elementsCategory:Transition metalsCategory:Precious metals ar:فضةast:Platazh-min-nan:Ag (goân-sò͘)bs:Srebrobg:Среброca:Platacs:Stříbroco:Argentucy:Arian (elfen)da:Sølvde:Silberet:Hõbees:Plataeo:Arĝentofa:نقرهfr:Argent (métal)ga:Airgead (dúil)gd:Airgead (meatailt)ko:은hy:Արծաթhr:Srebroio:Arjentoid:Perakis:Silfurit:Argentohe:כסף (יסוד)ka:ვერცხლიku:Zîvla:Argentumlv:Sudrabslb:Sëlwerlt:Sidabrasli:Zèlverjbo:rijnohu:Ezüstmi:Kawatams:Logam peraknl:Zilverja:銀no:Sølvnn:Sølvoc:Argentug:كۈمۈشnds:Sülverpl:Srebropt:Prataro:Argintru:Сереброscn:Argentusimple:Silversk:Striebrosl:Srebrosr:Среброsh:Srebrofi:Hopeasv:Silverta:வெள்ளிtt:Kömeşth:เงิน (ธาตุ)vi:Bạctg:Нуқраtr:Gümüşuk:Сріблоuz:Kumushzh-yue:銀zh:銀