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Silver
*** Shopping-Tip: Silver
{{Elementbox_header | number=47 | symbol=Ag | name=silver | left=
palladium .html">cadmium
_above=copper|Cu | below=
gold Au | color1=#ffc0c0 | color2=black }}
{{Elementbox_series |
transition metals }}
{{Elementbox_groupperiodblock | group=11 | period=5 | block=d }}
{{Elementbox_appearance_img | Ag,47| lustrous white metal }}
{{Elementbox_atomicmass_gpm |
1 E-25 kg 107.8682List of elements by atomic mass (2) }}
{{Elementbox_econfig | [
krypton Kr] 4d
10 5s
1 }}
{{Elementbox_epershell | 2, 8, 18, 18, 1 }}
{{Elementbox_section_physicalprop | color1=#ffc0c0 | color2=black }}
{{Elementbox_color |
silver (color) silver }}
{{Elementbox_phase |
solid }}
{{Elementbox_density_gpcm3nrt | 10.49 }}
{{Elementbox_densityliq_gpcm3mp | 9.320 }}
{{Elementbox_meltingpoint | k=1234.93 | c=961.78 | f=1763.2 }}
{{Elementbox_boilingpoint | k=2435 | c=2162 | f=3924 }}
{{Elementbox_heatfusion_kjpmol | 11.28 }}
{{Elementbox_heatvaporiz_kjpmol | 258 }}
{{Elementbox_heatcapacity_jpmolkat25 | 25.350 }}
{{Elementbox_vaporpressure_katpa | 1283 | 1413 | 1575 | 1782 | 2055 | 2433 | comment= }}
{{Elementbox_section_atomicprop | color1=#ffc0c0 | color2=black }}
{{Elementbox_crystalstruct | face-centered cubic }}
{{Elementbox_oxistates | 1
(
amphoteric oxide) }}
{{Elementbox_electroneg_pauling | 1.93 }}
{{Elementbox_ionizationenergies3 | 731.0 | 2070 | 3361 }}
{{Elementbox_atomicradius_pm |
1 E-10 m 160 }}
{{Elementbox_atomicradiuscalc_pm |
1 E-10 m 165 }}
{{Elementbox_covalentradius_pm |
1 E-10 m 153 }}
{{Elementbox_vanderwaalsrad_pm |
1 E-10 m 172 }}
{{Elementbox_section_miscellaneous | color1=#ffc0c0 | color2=black }}
{{Elementbox_magnetic |
diamagnetism diamagnetic }}
{{Elementbox_eresist_ohmmat20 | 15.87 n}}
{{Elementbox_thermalcond_wpmkat300k | 429 }}
{{Elementbox_thermaldiff_wpmkat300k | 174 }}
{{Elementbox_thermalexpansion_umpmkat25 | 18.9 }}
{{Elementbox_speedofsound_rodmpsatrt | 2680 }}
{{Elementbox_youngsmodulus_gpa | 83 }}
{{Elementbox_shearmodulus_gpa | 30 }}
{{Elementbox_bulkmodulus_gpa | 100 }}
{{Elementbox_poissonratio | 0.37 }}
{{Elementbox_mohshardness | 2.5 }}
{{Elementbox_vickershardness_mpa | 251 }}
{{Elementbox_brinellhardness_mpa | 24.5 }}
{{Elementbox_cas_number | 7440-22-4 }}
{{Elementbox_isotopes_begin | isotopesof=silver | color1=#ffc0c0 | color2=black }}
{{Elementbox_isotopes_decay2 | mn=105 | sym=Ag
| na=
synthetic radioisotope syn | hl=
1 E6 s 41.2 d
| dm1=
electron capture ε | de1=- | pn1=105 | ps1=
palladium Pd
| dm2=
gamma ray γ | de2=0.344, 0.280,
0.644, 0.443 | pn2= | ps2=- }}
{{Elementbox_isotopes_decay2 | mn=106
nuclear isomer m | sym=Ag
| na=
synthetic radioisotope syn | hl=
1 E5 s 8.28 d
| dm1=
electron capture ε | de1=- | pn1=106 | ps1=
palladium Pd
| dm2=
gamma ray γ | de2=0.511, 0.717,
1.045, 0.450 | pn2= | ps2=- }}
{{Elementbox_isotopes_stable | mn=107 | sym=Ag | na=51.839% | n=60 }}
{{Elementbox_isotopes_decay3 | mn=108
nuclear isomer m | sym=Ag
| na=
synthetic radioisotope syn | hl=
1 E10 s 418 y
| dm1=
electron capture ε | de1=- | pn1=108 | ps1=
palladium Pd
| dm2=
isomeric transition IT | de2=0.109 | pn2=108 | ps2=Ag
| dm3=
gamma ray γ | de3=0.433, 0.614,
0.722 | pn3= | ps3=-}}
{{Elementbox_isotopes_stable | mn=109 | sym=Ag | na=48.161% | n=62 }}
{{Elementbox_isotopes_decay2 | mn=111 | sym=Ag
| na=
synthetic radioisotope syn | hl=
1 E5 s 7.45 d
| dm1=
beta decay β- | de1=1.036, 0.694 | pn1=111 | ps1=
cadmium Cd
| dm2=
gamma ray γ | de2=0.342 | pn2= | ps2=- }}
{{Elementbox_isotopes_end}}
{{Elementbox_footer | color1=#ffc0c0 | color2=black }}
:''This page is about silver the
chemical element. For the
color, see
silver (color). See also
Silver (disambiguation)''
'''Silver''' is a
chemical element with the symbol '''Ag''' (from the traditional abbreviation for the
Latin (language) Latin ''argentum''). A soft white lustrous
transition metal, it has the highest electrical and thermal conductivity of any metal and occurs in
minerals and in free form. This metal is used in
coins,
jewelry,
tableware,
photography, and in mirrors.
Notable characteristics
Image:SilverUSGOV.jpg thumb|left|A chunk 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
polishing 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 with
sulfur in it. The most common
oxidation state of silver is +1 (for example,
silver nitrate; AgNO
3), a few +2 (for example,
silver(II) fluoride; AgF
2) and +3 compounds (for example,
silver(III) persulfate; Ag
2(SO
5)
3) are also known.
Applications
The principal use of silver is as a
precious metal. Its salts, especially
silver nitrate and silver
halogen 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 is also used in high voltage contacts because it is the only metal that will not arc across contacts, hence it is extremely safe.
*
Mirrors 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.
*Silver has been coined to produce money since
700 BC by the
Lydians, 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.
*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 from
methanol and air by means of silver screens or
crystallites containing a minimum 99.95
weight-percent silver. Silver (upon some suitable support) is probably the only catalyst available today to convery
ethylene to
ethylene oxide (later hydrolyzed to
ethylene glycol, used for making
polyesters)—a very important industrial reaction.
*Used to make
solder and brazing alloys,
electrical contacts, and high capacity silver-
zinc and silver-
cadmium Battery (electricity) batteries.
*
Silver sulfide, also known as
Silver Whiskers, is formed when silver
electrical contacts are used in an atmosphere rich in
hydrogen sulfide.
*
Silver fulminate is a powerful
explosive.
*
Silver chloride can be made transparent and is used as a
cement for glass.
*
Silver chloride is also a widely used electrode for
pH testing and
potentiometric measurement
*
Silver iodide has been used in attempts to seed
clouds to produce rain.
* In
legend, silver is traditionally seen as harmful to
supernatural creatures like
werewolves and
vampires. The use of silver fashioned into
bullets for
firearms is a popular application.
*
Silver oxide is used as a positive electrode (
cathode) in watch batteries.
*
Colloidal silver is a possible antibacterial / antibiotic treatment that requires further clinical testing to support actual efficacy.
*
Silver nitrate (liquid) and
silver sulfadiazine cream (SSD Cream) were the "standard of care" for the antibacterial/antibiotic treatment of serious burns until the late 1990's. Now, Acticoat Burn Dressings (activated silver dressings) have largely replaced those earlier treatments.
History
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
ornaments and
utensils, for
trade, and as the basis for many
monetary systems. Its value as a
precious metal was long considered second only to
gold. In
Ancient Egypt and
Middle Ages Medieval Europe, it was often more valuable than 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''.
image:silver-symbol.png right|75px|Alchemical symbol for silverOne of the
alchemy alchemical symbols for silver is a
crescent moon with the open part on the left (see picture, right).
The metal
mercury (element) mercury was thought of as a kind of silver, though the two elements are chemically unrelated; its Latin and
English language English names, ''hydrargyrum'' ("watery silver") and ''quicksilver,'' respectively, reflect this history.
In
heraldry, the
tincture (heraldry) 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 a huge amount of silver in the
New World in
Zacatecas, Zacatecas Zacatecas and
PotosÃ, 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
Spain Spanish Empire. The rise and fall of its value affected the world market.
The
Rio de la Plata was named after silver (in
Spanish language Spanish, ''plata''), 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 (lead, mostly) in the galena ore silver is most commonly found in. Notable
silver rush "silver rushes" were in
Colorado,
Nevada,
Cobalt, Ontario Cobalt, Ontario ,
California and the
Kootenays Kootenay region of British Columbia, notably in the
Boundary Country Boundary and
Slocan "Silvery Slocan". The largest silver ore deposits in the United States were discovered at the
Comstock Lode in Virginia City, Nevada, in 1859.
Occurrence
Image:SilverOreUSGOV.jpg thumb|left|Silver ore
{{See also|:Category:Silver minerals}}
Silver is found in native form, combined with
sulfur,
arsenic,
antimony, or
chlorine and in various ores such as
argentite (Ag
2sulfur S) and
horn silver (Ag
chlorine Cl).
The principal sources of silver are
copper, copper-
nickel,
gold,
lead and lead-
zinc ores obtained from
Canada,
Cobalt, Ontario Cobalt, Ontario ,
Mexico,
Peru,
Australia and the
United States.
This metal is also produced during the
electrolysis 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 80,120,000
troy weight troy ounces (2492
metric tons) in 2000, about 15% of the annual production of the world.
Price
Image:Johnson Matthey 500 grammes silver bullion.jpg Johnson_Matthey.html" title="Meaning of thumb thumb|right|143px|[[Johnson Matthey silver bullion bar.html" title="Meaning of right|143px|[[Johnson Matthey">thumb|right|143px|[[Johnson Matthey silver bullion bar">right|143px|[[Johnson Matthey">thumb|right|143px|[[Johnson Matthey silver bullion bar
{{Main articles|
Silver as an investment and
Silver standard}}
Silver is currently about 1/60th the price of gold by weight, and approximately 70 times more valuable than copper. Silver did once trade at 1/6th to 1/7th the price of gold, prior to the
Age of Discovery and the finding of large silver deposits in the Americas.
Over the last 100 years the price of silver and the gold/silver 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 $49.45 per
troy ounce. In December 2001 the silver price was $4.15 per ounce, and in February 2006 it had risen to $9.50 per ounce [http://kitco.com/LFgif/ag84-pres.gif].
Isotopes
Naturally occurring silver is composed of the two stable
isotopes Ag-107 and Ag-109 with Ag-107 being the more abundant (51.839%
natural abundance). Twenty-eight
radioisotopes have been characterised 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 Ag-128m (''t''
* 418 years), Ag-110m (''t''
* 249.79 days) and Ag-107m (''t''
* 8.28 days).
Isotopes of silver range in
atomic weight from 93.943
atomic mass unit u (Ag-94) to 123.929 u (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
palladium Pd/Ag ratio to yield measurable variations in Ag-107 abundance.
Radiogenic Ag-107 was first discovered in the
Santa Clara, California 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 (science) accretion of the
solar system, must reflect the presence of live short-lived nuclides in the early solar system.
Precautions and health effects
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 of its salts are, and some may be
carcinogenic.
Hippocrates, 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 dollars 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 antibiotics, and Silver compounds are still widely used externally today to accelerate healing in burn victims.
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 membranes. 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 (element) lead or
mercury (element) mercury, 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.
The widespread use of silver went out of fashion with the invention of
antibiotics.
In India, foods can be found decorated with a thin layer of silver, known as
Varak.
References
-
Los Alamos National Laboratory – Silver
See also
*
Precious metal
*
Silver as an investment
*
Silver coin
*
Silver standard
*
:category:Silver compounds Silver compounds.''
External links
{{Spoken |Silver.ogg|2005-09-01}}
{{Commons|Silver}}
{{wiktionary|silver}}
-
WebElements.com – Silver
-
Chart: Silver in Dollar
-
World mine production of silver, by country
-
The Silver Institute A silver industry website
-
A collection of silver items Samples of silver
Publications on health effects
-
Systemic argyria associated with ingestion of colloidal silver
-
Myoclonic status epilepticus following repeated oral ingestion of colloidal silver
-
Specific Inactivation of Herpes Simplex Virus by Silver Nitrate at Low Concentrations and Biological Activities of the Inactivated Virus
-
Prevention of Herpes Keratoconjunctivitis in Rabbits By Silver Sulfadiazine
Category:Chemical elements
Category:Transition metals
Category:Precious metals
Category:Silver
ar:Ù?ضة
bg:Сребро
ca:Plata
cs:StÅ™Ãbro
cy:Arian (elfen)
da:Sølv
de:Silber
et:Hõbe
es:Plata
eo:ArÄ?ento
fr:Argent
ga:Airgead (dúil)
ko:ì?€
io:Arjento
id:Perak
is:Silfur
it:Argento
he:כסף (יסוד)
ku:Zîv
lv:Sudrabs
lt:Sidabras
lb:Sëlwer
jbo:rijno
hu:Ezüst
mi:Kawata
nl:Zilver
nds:Sülver
ja:銀
li:Zèlver
no:Sølv
nn:Sølv
oc:Argent
pl:Srebro
pt:Prata
ro:Argint
ru:Серебро
sh:Srebro
scn:Argentu
simple:Silver
sl:Srebro
sr:Сребро
fi:Hopea
sv:Silver
ta:வெள�ளி
tt:Kömeş
th:เงิน
vi:Bạc
tr:Gümüş
uk:Срібло
zh:銀
Silver Ag
----
This template should be :Template substitution substituted.
Category:Chemical element symbol templates {{PAGENAME}}
{{commonscat|Silver}}
{{catmore}}
Silver is a
precious metal chemical element. It is an industrial commodity used in
photography and
electronics and is used for bullion, coins, jewellery and silversmithing.
Category:Transition metals
Category:Precious metals
Category:Chemical elements
*** Shopping-Tip: Silver
