Product Code Database
Silver is a chemical element; it has symbol Ag () and atomic number 47. A soft, whitish-gray, lustrous transition metal, it exhibits the highest electrical conductivity, thermal conductivity, and reflectivity of any metal. Silver is found in the Earth's crust in the pure, free elemental form ("native metal silver"), as an alloy with gold and other metals, and in minerals such as argentite and chlorargyrite. Most silver is produced as a byproduct of copper, gold, lead, and zinc refining.
Silver has long been valued as a precious metal, commonly sold and marketed beside gold and platinum. Silver metal is used in many , sometimes bimetallism: while it is more abundant than gold, it is much less abundant as a native metal. Its purity is typically measured on a per-mille basis; a 94%-pure alloy is described as "0.940 fine". As one of the seven metals of antiquity, silver has had an enduring role in most human cultures. In terms of scarcity, silver is the most abundant of the big three precious metals—platinum, gold, and silver—among these, platinum is the rarest with around 139 Troy weight of silver mined for every one ounce of platinum.
Other than in currency and as an investment medium (coins and bullion), silver is used in solar panels, water filtration, jewellery, ornaments, high-value tableware and utensils (hence the term "silverware"), in electrical contacts and conductors, in specialised mirrors, window coatings, in catalysis of chemical reactions, as a colorant in stained glass, and in specialised confectionery. Its compounds are used in photographic and X-ray film. Dilute solutions of silver nitrate and other silver compounds are used as and microbiocides (oligodynamic effect), added to , wound-dressings, , and other medical instruments.
Silver is a relatively soft and extremely Ductility and Malleability transition metal, though it is slightly less malleable than gold. Silver crystallises in a face-centred cubic lattice with bulk coordination number 12, where only the single 5s electron is delocalised, similarly to copper and gold.Greenwood and Earnshaw, p. 1178 Unlike metals with incomplete d-shells, metallic bonds in silver are lacking a covalent bond character and are relatively weak. This observation explains the low hardness and high ductility of monocrystalline of silver.
Silver has a brilliant, white, metallic luster that can take a high polishing, and which is so characteristic that the name of the metal itself has become a color name.Greenwood and Earnshaw, p. 1177 Protected silver has greater optical reflectivity than aluminium at all wavelengths longer than ~450 nm. At wavelengths shorter than 450 nm, silver's reflectivity is inferior to that of aluminium and drops to zero near 310 nm.
Very high electrical and thermal conductivity are common to the elements in group 11, because their single s electron is free and does not interact with the filled d subshell, as such interactions (which occur in the preceding transition metals) lower electron mobility. (2025). 9780471649526, John Wiley & Sons. ISBN 9780471649526 The thermal conductivity of silver is among the highest of all materials, although the thermal conductivity of carbon (in the diamond Allotropy) and superfluid helium-4 are higher. The electrical conductivity of silver is the highest of all metals, greater even than copper. Silver also has the lowest contact resistance of any metal. Silver is rarely used for its electrical conductivity, due to its high cost, although an exception is in radio-frequency engineering, particularly at VHF and higher frequencies where silver plating improves electrical conductivity because those Skin effect rather than through the interior. During World War II in the US, tons of silver were used for the electromagnets in for enriching uranium, mainly because of the wartime shortage of copper.
Silver readily forms with copper, gold, and zinc. Zinc-silver alloys with low zinc concentration may be considered as face-centred cubic solid solutions of zinc in silver, as the structure of the silver is largely unchanged while the electron concentration rises as more zinc is added. Increasing the electron concentration further leads to body-centred cubic (electron concentration 1.5), complex cubic (1.615), and hexagonal close-packed phases (1.75).
Twenty-eight have been characterised, 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. Silver has numerous , the most stable being 108mAg ( t1/2 = 418 years), 110mAg ( t1/2 = 249.79 days) and 106mAg ( t1/2 = 8.28 days). All of the remaining radioactive isotopes have half-lives of less than an hour, and the majority of these have half-lives of less than three minutes.
Isotopes of silver range in atomic mass from 92.950 Da (93Ag) to 129.950 Da (130Ag); the primary decay mode before the most abundant stable isotope, 107Ag, is electron capture and the primary mode after is beta decay. The primary before 107Ag are palladium (element 46) isotopes, and the primary products after are cadmium (element 48) isotopes.
The palladium isotope 107Pd decays by beta emission to 107Ag with a half-life of 6.5 million years. are the only objects with a high-enough palladium-to-silver ratio to yield measurable variations in 107Ag abundance. Radiogenic 107Ag was first discovered in the Santa Clara meteorite in 1978. 107Pd–107Ag correlations observed in bodies that have clearly been melted since the accretion of the Solar System must reflect the presence of unstable nuclides in the early Solar System.
| + Oxidation states and stereochemistries of silver |
| Ag(CO)3 |
| Ag(CN)2− |
| AgI(PEt2Ar)2 |
| Ag(diars)2+ |
| AgF, AgCl, AgBr |
| Ag(py)42+ |
| AgF4− |
| AgF63− |
Most silver compounds have significant covalent bond character due to the small size and high first ionisation energy (730.8 kJ/mol) of silver. Furthermore, silver's Pauling electronegativity of 1.93 is higher than that of lead (1.87), and its electron affinity of 125.6 kJ/mol is much higher than that of hydrogen (72.8 kJ/mol) and not much less than that of oxygen (141.0 kJ/mol).Greenwood and Earnshaw, p. 1176 Due to its full d-subshell, silver in its main +1 oxidation state exhibits relatively few properties of the transition metals proper from groups 4 to 10, forming rather unstable organometallic compounds, forming linear complexes showing very low coordination numbers like 2, and forming an amphoteric oxideLidin RA 1996, Inorganic substances handbook, Begell House, New York, . p. 5 as well as like the post-transition metals.Goodwin F, Guruswamy S, Kainer KU, Kammer C, Knabl W, Koethe A, Leichtfreid G, Schlamp G, Stickler R & Warlimont H 2005, 'Noble metals and noble metal alloys', in Springer Handbook of Condensed Matter and Materials Data, W Martienssen & H Warlimont (eds), Springer, Berlin, pp. 329–406, . p. 341 Unlike the preceding transition metals, the +1 oxidation state of silver is stable even in the absence of pi backbonding.
Silver does not react with air, even at red heat, and thus was considered by as a noble metal, along with gold. Its reactivity is intermediate between that of copper (which forms copper(I) oxide when heated in air to red heat) and gold. Like copper, silver reacts with sulfur and its compounds; in their presence, silver tarnishes in air to form the black silver sulfide (copper forms the green sulfate instead, while gold does not react). While silver is not attacked by non-oxidising acids, the metal dissolves readily in hot concentrated sulfuric acid, as well as dilute or concentrated nitric acid. In the presence of air, and especially in the presence of hydrogen peroxide, silver dissolves readily in aqueous solutions of cyanide.Greenwood and Earnshaw, p. 1179
The three main forms of deterioration in historical silver artifacts are tarnishing, formation of silver chloride due to long-term immersion in salt water, as well as reaction with nitrate ions or oxygen. Fresh silver chloride is pale yellow, becoming purplish on exposure to light; it projects slightly from the surface of the artifact or coin. The precipitation of copper in ancient silver can be used to date artifacts, as copper is nearly always a constituent of silver alloys. "Silver Artifacts" in Corrosion – Artifacts. NACE Resource Center
Silver metal is attacked by strong Oxidizing agent such as potassium permanganate () and potassium dichromate (), and in the presence of potassium bromide (). These compounds are used in photography to bleach silver images, converting them to silver bromide that can either be fixed with thiosulfate or redeveloped to intensify the original image. Silver forms cyanide complexes (silver cyanide) that are soluble in water in the presence of an excess of cyanide ions. Silver cyanide solutions are used in electroplating of silver.
The common of silver are (in order of commonness): +1 (the most stable state; for example, silver nitrate, AgNO3); +2 (highly oxidising; for example, silver(II) fluoride, AgF2); and even very rarely +3 (extreme oxidising; for example, potassium tetrafluoroargentate(III), KAgF4). The +3 state requires very strong oxidising agents to attain, such as fluorine or peroxodisulfate, and some silver(III) compounds react with atmospheric moisture and attack glass.Greenwood and Earnshaw, p. 1188 Indeed, silver(III) fluoride is usually obtained by reacting silver or silver monofluoride with the strongest known oxidising agent, krypton difluoride.Greenwood and Earnshaw, p. 903
Silver(I) sulfide, Ag2S, is very readily formed from its constituent elements and is the cause of the black tarnish on some old silver objects. It may also be formed from the reaction of hydrogen sulfide with silver metal or aqueous Ag+ ions. Many non-stoichiometric and tellurides are known; in particular, AgTe~3 is a low-temperature superconductor.
In stark contrast to this, all four silver(I) halides are known. The fluoride, silver chloride, and silver bromide have the sodium chloride structure, but the silver iodide has three known stable forms at different temperatures; that at room temperature is the cubic zinc blende structure. They can all be obtained by the direct reaction of their respective elements. As the halogen group is descended, the silver halide gains more and more covalent character, solubility decreases, and the colour changes from the white chloride to the yellow iodide as the energy required for ligand-metal charge transfer (X−Ag+ → XAg) decreases. The fluoride is anomalous, as the fluoride ion is so small that it has a considerable solvation energy and hence is highly water-soluble and forms di- and tetrahydrates. The other three silver halides are highly insoluble in aqueous solutions and are very commonly used in gravimetric Wet chemistry methods. All four are photosensitive (though the monofluoride is so only to ultraviolet light), especially the bromide and iodide which photodecompose to silver metal, and thus were used in traditional photography. The reaction involved is:Greenwood and Earnshaw, pp. 1185–87
The process is not reversible because the silver atom liberated is typically found at a crystal defect or an impurity site, so that the electron's energy is lowered enough that it is "trapped".
Yellow silver carbonate, Ag2CO3 can be easily prepared by reacting aqueous solutions of sodium carbonate with a deficiency of silver nitrate. Its principal use is for the production of silver powder for use in microelectronics. It is reduced with formaldehyde, producing silver free of alkali metals:Brumby et al.
Silver carbonate is also used as a reagent in organic synthesis such as the Koenigs–Knorr reaction. In the Fétizon oxidation, silver carbonate on celite acts as an oxidising agent to form from diols. It is also employed to convert alkyl bromides into alcohols.
Silver fulminate, AgCNO, a powerful, touch-sensitive explosive used in , is made by reaction of silver metal with nitric acid in the presence of ethanol. Other dangerously explosive silver compounds are silver azide, AgN3, formed by reaction of silver nitrate with sodium azide, and silver acetylide, Ag2C2, formed when silver reacts with acetylene gas in ammonia solution. In its most characteristic reaction, silver azide decomposes explosively, releasing nitrogen gas: given the photosensitivity of silver salts, this behaviour may be induced by shining a light on its crystals.
Silver(II) complexes are more common. Like the valence isoelectronic copper(II) complexes, they are usually square planar and paramagnetic, which is increased by the greater field splitting for 4d electrons than for 3d electrons. Aqueous Ag2+, produced by oxidation of Ag+ by ozone, is a very strong oxidising agent, even in acidic solutions: it is stabilised in phosphoric acid due to complex formation. Peroxodisulfate oxidation is generally necessary to give the more stable complexes with heterocyclic , such as Ag(py)42+ and Ag(bipy)22+: these are stable provided the counterion cannot reduce the silver back to the +1 oxidation state. AgF42− is also known in its violet barium salt, as are some silver(II) complexes with N- or O-donor ligands such as pyridine carboxylates.Greenwood and Earnshaw, p. 1189
By far the most important oxidation state for silver in complexes is +1. The Ag+ cation is diamagnetic, like its homologues Cu+ and Au+, as all three have closed-shell electron configurations with no unpaired electrons: its complexes are colourless provided the ligands are not too easily polarised such as I−. Ag+ forms salts with most anions, but it is reluctant to coordinate to oxygen and thus most of these salts are insoluble in water: the exceptions are the nitrate, perchlorate, and fluoride. The tetracoordinate tetrahedral aqueous ion Ag(H2O)4+ is known, but the characteristic geometry for the Ag+ cation is 2-coordinate linear. For example, silver chloride dissolves readily in excess aqueous ammonia to form Ag(NH3)2+; silver salts are dissolved in photography due to the formation of the thiosulfate complex Ag(S2O3)23−; and cyanide extraction for silver (and gold) works by the formation of the complex Ag(CN)2−. Silver cyanide forms the linear polymer {Ag–C≡N→Ag–C≡N→}; silver thiocyanate has a similar structure, but forms a zigzag instead because of the sp3-hybridized sulfur atom. are unable to form linear complexes and thus silver(I) complexes with them tend to form polymers; a few exceptions exist, such as the near-tetrahedral diphosphine and diarsine complexes Ag(L–L)2+.Greenwood and Earnshaw, pp. 1195–96
The C–Ag bond is stabilised by perfluoroalkane ligands, for example in AgCF(CF3)2. Alkenylsilver compounds are also more stable than their alkylsilver counterparts. Silver-NHC complexes are easily prepared, and are commonly used to prepare other NHC complexes by displacing labile ligands. For example, the reaction of the bis(NHC)silver(I) complex with bis(acetonitrile)palladium dichloride or chlorido(dimethyl sulfide)gold(I):
Most other binary alloys are of little use: for example, silver–gold alloys are too soft and silver–cadmium alloys too toxic. Ternary alloys have much greater importance: dental amalgams are usually silver–tin–mercury alloys, silver–copper–gold alloys are very important in jewellery (usually on the gold-rich side) and have a vast range of hardnesses and colours, silver–copper–zinc alloys are useful as low-melting brazing alloys, and silver–cadmium–indium (involving three adjacent elements on the periodic table) is useful in because of its high thermal neutron capture cross-section, good conduction of heat, mechanical stability, and resistance to corrosion in hot water.
The chemical symbol Ag is from the Latin word for silver, argentum (compare Ancient Greek ἄργυρος, ), from the Proto-Indo-European root * h₂erǵ- (formerly reconstructed as *arǵ-), meaning or . This was the usual Proto-Indo-European word for the metal, whose reflexes are missing in Germanic and Balto-Slavic.
The situation changed with the discovery of cupellation, a technique that allowed silver metal to be extracted from its ores. While 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, and one of the earliest silver extraction centres in Europe was Sardinia in the early Chalcolithic period,Melis, Maria Grazia (2025). 9783944507057, Landesamt für Denkmalpflege und Archäologie Sachsen-Anhalt. . ISBN 9783944507057 these techniques did not spread widely until later,
when it spread throughout the region and beyond. The origins of silver production in India, China, and Japan were almost certainly equally ancient, but are not well-documented due to their great age.
When the first came to what is now Spain, they obtained so much silver that they could not fit it all on their ships, and as a result used silver to weight their anchors instead of lead. By the time of the Greek and Roman civilisations, silver coins were a staple of the economy: the Greeks were already extracting silver from galena by the 7th century BC, and the rise of Athens was partly made possible by the nearby silver mines at Laurium, from which they extracted about 30 tonnes a year from 600 to 300 BC. The stability of the Roman currency relied to a high degree on the supply of silver bullion, mostly from Spain, which Roman metallurgy produced on a scale unparalleled before the discovery of the New World. Reaching a peak production of 200 tonnes per year, an estimated silver stock of 10,000 tonnes circulated in the Roman economy in the middle of the second century AD, five to ten times larger than the combined amount of silver available to medieval Europe and the Abbasid Caliphate around AD 800. The Romans also recorded the extraction of silver in central and northern Europe in the same time period. This production came to a nearly complete halt with the fall of the Roman Empire, not to resume until the time of Charlemagne: by then, tens of thousands of tonnes of silver had already been extracted.Brumby et al., pp. 16–19
Central Europe became the centre of silver production during the Middle Ages, as the Mediterranean deposits exploited by the ancient civilisations had been exhausted. Silver mines were opened in Bohemia, Saxony, Alsace, the Lahn region, Siegerland, Silesia, Hungary, Norway, Steiermark, Schwaz, and the southern Black Forest. Most of these ores were quite rich in silver and could simply be separated by hand from the remaining rock and then smelted; some deposits of native silver were also encountered. Many of these mines were soon exhausted, but a few of them remained active until the Industrial Revolution, before which the world production of silver was around a meagre 50 tonnes per year. In the Americas, high temperature silver-lead cupellation technology was developed by pre-Inca civilisations as early as AD 60–120; silver deposits in India, China, Japan, and pre-Columbian America continued to be mined during this time.
With the discovery of America and the plundering of silver by the Spanish conquistadors, Central and South America became the dominant producers of silver until around the beginning of the 18th century, particularly Peru, Bolivia, Chile, and Argentina: the last of these countries later took its name from that of the metal that composed so much of its mineral wealth. The silver trade gave way to a global network of exchange. As one historian put it, silver "went round the world and made the world go round." Much of this silver ended up in the hands of the Chinese. A Portuguese merchant in 1621 noted that silver "wanders throughout all the world... before flocking to China, where it remains as if at its natural centre". Still, much of it went to Spain, allowing Spanish rulers to pursue military and political ambitions in both Europe and the Americas. "New World mines", concluded several historians, "supported the Spanish empire."
In the 19th century, primary production of silver moved to North America, particularly Canada, Mexico, and Nevada in the United States: some secondary production from lead and zinc ores also took place in Europe, and deposits in Siberia and the Russian Far East as well as in Australia were mined. Poland emerged as an important producer during the 1970s after the discovery of copper deposits that were rich in silver, before the centre of production returned to the Americas the following decade. Today, Peru and Mexico are still among the primary silver producers, but the distribution of silver production around the world is quite balanced and about one-fifth of the silver supply comes from recycling instead of new production.
In folklore, silver was commonly thought to have mystic powers: for example, a silver bullet is often supposed in such folklore the only weapon that is effective against a werewolf, witch, or other . From this the idiom of a silver bullet developed into figuratively referring to any simple solution with very high effectiveness or almost miraculous results, as in the widely discussed software engineering paper "No Silver Bullet." Other powers attributed to silver include detection of poison and facilitation of passage into the Fairyland.
Silver production has also inspired figurative language. Clear references to cupellation occur throughout the Old Testament of the Bible, such as in Jeremiah's rebuke to Judah: "The bellows are burned, the lead is consumed of the fire; the founder melteth in vain: for the wicked are not plucked away. Reprobate silver shall men call them, because the Lord hath rejected them." (Jeremiah 6:19–20) Jeremiah was also aware of sheet silver, exemplifying the malleability and ductility of the metal: "Silver spread into plates is brought from Tarshish, and gold from Uphaz, the work of the workman, and of the hands of the founder: blue and purple is their clothing: they are all the work of cunning men." (Jeremiah 10:9)
Silver also has more negative cultural meanings: the idiom , referring to a reward for betrayal, references the bribe Judas Iscariot is said in the New Testament to have taken from Jewish leaders in Jerusalem to turn Jesus over to soldiers of the high priest Caiaphas. Ethically, silver also symbolizes greed and degradation of consciousness; this is the negative aspect, the perverting of its value. (2025). 9789734612864, Polirom. ISBN 9789734612864
The principal sources of silver are the ores of copper, copper-nickel, lead, and lead-zinc obtained from Peru, Bolivia, Mexico, China, Australia, Chile, Poland and Serbia. Peru, Bolivia and Mexico have been mining silver since 1546, and are still major world producers. Top silver-producing mines are Cannington Mine (Australia), Fresnillo (Mexico), San Cristóbal (Bolivia), Antamina mine (Peru), Rudna mine (Poland), and Penasquito (Mexico). Top near-term mine development projects through 2015 are Pascua Lama (Chile), Navidad (Argentina), Jaunicipio (Mexico), Malku Khota (Bolivia), and Hackett River (Canada). In Central Asia, Tajikistan is known to have some of the largest silver deposits in the world.
Silver is usually found in nature combined with other metals, or in minerals that contain silver compounds, generally in the form of sulfides such as galena (lead sulfide) or cerussite (lead carbonate). So the primary production of silver requires the smelting and then cupellation of argentiferous lead ores, a historically important process.Kassianidou, V. (2003). "Early Extraction of Silver from Complex Polymetallic Ores", pp. 198–206 in Craddock, P.T. and Lang, J (eds.) Mining and Metal production through the Ages. London, British Museum Press. Lead melts at 327 °C, lead oxide at 888 °C and silver melts at 960 °C. To separate the silver, the alloy is melted again at the high temperature of 960 °C to 1000 °C in an oxidising environment. The lead oxidises to lead monoxide, then known as litharge, which captures the oxygen from the other metals present. The liquid lead oxide is removed or absorbed by capillary action into the hearth linings.Craddock, P.T. (1995). Early metal mining and production. Edinburgh: Edinburgh University Press. p. 223.
Bayley, J., Crossley, D. and Ponting, M. (eds). (2008). Metals and Metalworking. A research framework for archaeometallurgy
"Late Uruk silver production by cupellation at Habuba Kabira, Syria", pp. 123–34 in Metallurgica Antiqua, Deutsches Bergbau-Museum.
Today, silver metal is primarily produced instead as a secondary byproduct of electrolytic refining of copper, lead, and zinc, and by application of the Parkes process on lead bullion from ore that also contains silver. In such processes, silver follows the non-ferrous metal in question through its concentration and smelting, and is later purified out. For example, in copper production, purified copper is electrolysis deposited on the cathode, while the less reactive precious metals such as silver and gold collect under the anode as the so-called "anode slime". This is then separated and purified of base metals by treatment with hot aerated dilute sulfuric acid and heating with lime or silica flux, before the silver is purified to over 99.9% purity via electrolysis in nitrate solution.
Commercial-grade fine silver is at least 99.9% pure, and purities greater than 99.999% are available. In 2022, Mexico was the top producer of silver (6,300 or 24.2% of the world's total of 26,000 t), followed by China (3,600 t) and Peru (3,100 t).
In the Atlantic and Pacific, silver concentrations are minimal at the surface but rise in deeper waters. Silver is taken up by plankton in the photic zone, remobilized with depth, and enriched in deep waters. Silver is transported from the Atlantic to the other oceanic water masses. In North Pacific waters, silver is remobilised at a slower rate and increasingly enriched compared to deep Atlantic waters. Silver has increasing concentrations that follow the major oceanic conveyor belt that cycles water and nutrients from the North Atlantic to the South Atlantic to the North Pacific.
There is not an extensive amount of data focused on how marine life is affected by silver despite the likely deleterious effects it could have on organisms through bioaccumulation, association with particulate matters, and sorption. Not until about 1984 did scientists begin to understand the chemical characteristics of silver and the potential toxicity. In fact, mercury is the only other trace metal that surpasses the toxic effects of silver; the full silver toxicity extent is not expected in oceanic conditions because of its tendency to transfer into nonreactive biological compounds.
In one study, the presence of excess ionic silver and silver caused bioaccumulation effects on zebrafish organs and altered the chemical pathways within their gills. In addition, very early experimental studies demonstrated how the toxic effects of silver fluctuate with salinity and other parameters, as well as between life stages and different species such as finfish, molluscs, and crustaceans. Another study found raised concentrations of silver in the muscles and liver of dolphins and whales, indicating pollution of this metal within recent decades. Silver is not an easy metal for an organism to eliminate and elevated concentrations can cause death.
The ratio between the amount of silver used for coinage and that used for other purposes has fluctuated greatly over time; for example, in wartime, more silver tends to have been used for coinage to finance the war.Brumby et al., pp. 63–65
Today, silver bullion has the ISO 4217 currency code XAG, one of only four to have one (the others being platinum, palladium, and gold). Silver coins are produced from cast rods or ingots, rolled to the correct thickness, heat-treated, and then used to cut planchet from. These blanks are then milled and minted in a coining press; modern coining presses can produce 8,000 silver coins per hour.
Because pure silver is very soft, most silver used for these purposes is alloyed with copper, with finenesses of 925/1000, 835/1000, and 800/1000 being common. One drawback is the easy tarnishing of silver in the presence of hydrogen sulfide and its derivatives. Including precious metals such as palladium, platinum, and gold gives resistance to tarnishing but is quite costly; like zinc, cadmium, silicon, and germanium do not totally prevent corrosion and tend to affect the lustre and colour of the alloy. Electrolytically refined pure silver plating is effective at increasing resistance to tarnishing. The usual solutions for restoring the lustre of tarnished silver are dipping baths that reduce the silver sulfide surface to metallic silver, and cleaning off the layer of tarnish with a paste; the latter approach also has the welcome side effect of polishing the silver concurrently.
Colour photography requires the addition of special dye components and sensitisers, so that the initial black-and-white silver image couples with a different dye component. The original silver images are bleached off and the silver is then recovered and recycled. Silver nitrate is the starting material in all cases.Brumby et al., p. 82
The market for silver nitrate and silver halides for photography has rapidly declined with the rise of digital cameras. From the peak global demand for photographic silver in 1999 (267,000,000 or 8,304.6 ) the market contracted almost 70% by 2013.
Photochromic lenses include silver halides, so that ultraviolet light in natural daylight liberates metallic silver, darkening the lenses. The silver halides are reformed in lower light intensities. Colourless silver chloride films are used in radiation detectors. Zeolite sieves incorporating Ag+ ions are used to Desalination seawater during rescues, using silver ions to precipitate chloride as silver chloride. Silver is also used for its antibacterial properties for water sanitisation, but the application of this is limited by limits on silver consumption. Colloidal silver is similarly used to disinfect closed swimming pools; while it has the advantage of not giving off a smell like hypochlorite treatments do, colloidal silver is not effective enough for more contaminated open swimming pools. Small silver iodide crystals are used in cloud seeding to cause rain.Brumby et al., pp. 83–84
The Texas Legislature designated silver the official precious metal of Texas in 2007. (2025). 9781625110664, Texas State Historical Association. ISBN 9781625110664
In large doses, silver and compounds containing it can be absorbed into the circulatory system and become deposited in various body tissues, leading to argyria, which results in a blue-grayish pigmentation of the skin, eyes, and . Argyria is rare, and so far as is known, does not otherwise harm a person's health, though it is disfiguring and usually permanent. Mild forms of argyria are sometimes mistaken for cyanosis, a blue tint on skin, caused by lack of oxygen.
Metallic silver, like copper, is an antibacterial agent, which was known to the ancients and first scientifically investigated and named the oligodynamic effect by Carl Nägeli. Silver ions damage the metabolism of bacteria even at such low concentrations as 0.01–0.1 milligrams per litre; metallic silver has a similar effect due to the formation of silver oxide. This effect is lost in the presence of sulfur due to the extreme insolubility of silver sulfide.
Some silver compounds are very explosive, such as the nitrogen compounds silver azide, silver amide, and silver fulminate, as well as silver acetylide, silver oxalate, and silver(II) oxide. They can explode on heating, force, drying, illumination, or sometimes spontaneously. To avoid the formation of such compounds, ammonia and acetylene should be kept away from silver equipment. Salts of silver with strongly oxidising acids such as silver chlorate and silver nitrate can explode on contact with materials that can be readily oxidised, such as organic compounds, sulfur and soot.
|
|
