Argentum Argentumov

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Silver is a metallic chemical element with the chemical symbol Ag (Latin: argentum, from the Indo-European root *arg- for "white" or "shining") and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal. The metal occurs naturally in its pure, free form (native silver), as an alloy with gold and other metals, and in minerals such as argentite and chlorargyrite. Most silver is produced as a by-product of copper, gold, lead, and zinc refining. Silver has long been valued as a precious metal, and it is used to make ornaments, jewelry, high-value tableware, utensils (hence the term silverware), and currency coins. Today, silver metal is also used in electrical contacts and conductors, in mirrors and in catalysis of chemical reactions. Its compounds are used in photographic film and dilute silver nitrate solutions and other silver compounds are used as disinfectants and microbiocides. While many medical antimicrobial uses of silver have been supplanted by antibiotics, further research into clinical potential continues. Contents [hide] * 1 Characteristics * 2 Creation * 3 Isotopes * 4 Compounds * 5 Applications o 5.1 Currency o 5.2 Jewelry and silverware o 5.3 Dentistry o 5.4 Photography and electronics o 5.5 Mirrors and optics o 5.6 Other industrial and commercial applications o 5.7 Medicinal o 5.8 Clothing * 6 History * 7 Occurrence and extraction * 8 Price * 9 Precautions o 9.1 Monitoring excessive human exposure * 10 See also * 11 References * 12 External links Characteristics Silver 1000 oz (~30 kg) bullion bar Silver is a very ductile and malleable (slightly harder than gold) monovalent 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 tendency to tarnish have prevented it from being widely used in place of copper for electrical purposes. Despite this, 13, 540 tons were used in the electromagnets used for enriching uranium during World War II (mainly because of the wartime shortage of copper).[1][2] Another notable exception is in high-end audio cables.[3] Among metals, pure silver has the highest thermal conductivity[4] (the non-metal diamond and superfluid helium II are higher) and one of the highest optical reflectivity.[5] (Aluminium slightly outdoes silver in parts of the visible spectrum, and silver is a poor reflector of ultraviolet light). Silver also has the lowest contact resistance of any metal. Silver halides are photosensitive and are remarkable for their ability to record a latent image that can later be developed chemically. Silver is stable in pure air and water, but tarnishes when it is exposed to air or water containing ozone or hydrogen sulfide to form a black layer of silver sulfide which can be cleaned off with dilute hydrochloric acid.[6] The most common oxidation state of silver is +1 (for example, silver nitrate: AgNO3); in addition, +2 compounds (for example, silver(II) fluoride: AgF2) and the less common +3 compounds (for example, potassium tetrafluoroargentate: K[AgF4] ) are known. Creation Silver is created via the long S-process in low-medium mass stars (.6 -> 10 solar masses). This takes thousands of years to do. Isotopes Main article: Isotopes of silver Naturally occurring silver is composed of two stable isotopes, 107Ag and 109Ag, with 107Ag being the most abundant (51.839% natural abundance). Silver's atomic weight is 107.8682(2) g/mol.[7][8] Twenty-eight radioisotopes have been characterized, the most stable being 105Ag with a half-life of 41.29 days, 111Ag with a half-life of 7.45 days, and 112Ag with a half-life of 3.13 hours. This element has numerous meta states, the most stable being 108mAg (t1/2 = 418 years), 110mAg (t1/2 = 249.79 days) and 106mAg (t1/2