Misplaced Pages

#160839

119-405: A medal may be awarded to a person or organisation as a form of recognition for sporting, military, scientific, cultural, academic, or various other achievements. Military awards and decorations are more precise terms for certain types of state decoration . Medals may also be created for sale to commemorate particular individuals or events, or as works of artistic expression in their own right. In

238-486: A bullet cast from silver is often supposed in such folklore the only weapon that is effective against a werewolf , witch , or other monsters . 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

357-419: A color name . 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

476-411: A motto , privy mark , engraver symbol, assayer's marking, or a series number. Medals that are intended to be hung from a ribbon also include a small suspension piece at the crest with which to loop a suspension ring through. It is through the ring that a ribbon is run or folded so the medal may hang pendent. Medals pinned to the breast use only a small cut of ribbon that is attached to a top bar where

595-599: A pendant (commonly a medal ) attached. The oldest military decorations still in use is Sweden's För tapperhet i fält ('For Valour in the Field') and För tapperhet till sjöss ('For Valour at Sea') awarded to officers and soldiers of the Swedish Armed Forces who have—as the medal names suggest—shown valour in the field or at sea in wartime. The medal was instituted by Swedish king Gustav III on 28 May 1789, during his war against Russia. Whilst technically it

714-408: A chain. From the 16th century onward, medals were made, both by rulers for presentation and private enterprise for sale, to commemorate specific events, including military battles and victories, and from this grew the practice of awarding military medals specifically to combatants, though initially only a few of the much higher-ranking officers. The medieval revival seems to have begun around 1400 with

833-541: A medal as its insignia, however, most tend to have a unique badge or a type of plaque specifically designed for an emblem. The Medal of Honor is the highest military decoration awarded by the United States Government , and is an example of a decoration that is modeled as a military order, even though not expressly defining itself as one (The Legion of Merit distinctly serves this purpose, and unlike any other U.S. military decoration, has classes). It

952-592: A non-Indo-European Wanderwort . Some scholars have thus proposed a Paleo-Hispanic origin, pointing to the Basque form zilharr as an evidence. The chemical symbol Ag is from the Latin word for silver , argentum (compare Ancient Greek ἄργυρος , árgyros ), from the Proto-Indo-European root * h₂erǵ- (formerly reconstructed as *arǵ- ), meaning ' white ' or ' shining ' . This

1071-464: A number of portrait medals of princes and scholars in the 1440s. Many other artists followed his example, in places such as Italy, the Low Countries, Germany, and France. In the seventeenth century medals were extensively used to commemorate events and glorify rulers. In the eighteenth century prize medals became common. In the 19th century art medals exploded in popularity. In the early part of

1190-467: A range of metals, such as gold, silver-gilt , silver, bronze, and lead, depending on the status of the recipient. They were typically up to about three inches across, and usually featured the head of the donor on the obverse, surrounded by an inscription with their name and title, and their emblem on the reverse, with a learned motto inscribed round the edges. Such medals were not usually intended to be worn, although they might have been set as pendants on

1309-614: 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 of Nazareth 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. The abundance of silver in the Earth's crust is 0.08  parts per million , almost exactly

SECTION 10

#1732772304161

1428-629: 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

1547-407: A single electron in the highest occupied s subshell over a filled d subshell, accounts for many of the singular properties of metallic silver. Silver is a relatively soft and extremely ductile and malleable transition metal , though it is slightly less malleable than gold. Silver crystallizes in a face-centered cubic lattice with bulk coordination number 12, where only the single 5s electron

1666-402: A single impact. Circular medals are most common; rectangular medals are often known as plaquettes , and square medals as klippe . The "decoration" types often use other shapes, especially crosses and stars. These in particular usually come with a suspension loop, and a wide coloured ribbon with a clip at the top, for attaching to clothing worn on the chest. The main or front surface of a medal

1785-596: A variety of achievements. The practice was revived in the Early Modern period, and medals began to be worn on the chest as part of standard military uniform . The United States Continental Congress awarded the Fidelity Medallion as early as 1780, to three specified men for a particular incident, as a one-off award, which was characteristic of early military decorations. In 1782, the Badge of Military Merit

1904-412: A variety of other ways to improve their appearance. Medals have also been made of rock , gemstone , ivory , glass , porcelain , terra cotta , coal , wood , paper , enamel , lacquerware , and plastics .Today, a large number of common events use zinc alloys for their medals, due to their low melting point, ease of casting and low price. The first known instance of a medal being awarded comes from

2023-664: A victory was struck for Francesco Carrara (Novello) on the occasion of the capture of Padua in 1390. The Italian artist Pisanello , generally agreed to be the finest medallist of the Renaissance , began in 1438 with a medal , celebrating the unprecedented visit of the Byzantine Emperor John VIII Palaiologos to Italy. This was presumably a commercial venture, but his later medals were mostly commissioned for distribution as gifts by rulers or nobles. Like almost all early Renaissance medals, it

2142-560: A wall, table top, desk, or cabinet. Numismatists divide medals into at least seven classes: First attested in English in 1578, the word medal is derived from the Middle French médaille , itself from Italian medaglia , and ultimately from the post-classical Latin medalia , meaning a coin worth half a denarius . The word medallion (first attested in English in 1658) has the same ultimate derivation, but this time through

2261-567: Is cognate with Old High German silabar ; Gothic silubr ; or Old Norse silfr , all ultimately deriving from Proto-Germanic *silubra . The Balto-Slavic words for silver are rather similar to the Germanic ones (e.g. Russian серебро [ serebró ], Polish srebro , Lithuanian sidãbras ), as is the Celtiberian form silabur . They may have a common Indo-European origin, although their morphology rather suggest

2380-465: Is the difluoride , AgF 2 , which can be obtained from the elements under heat. A strong yet thermally stable and therefore safe fluorinating agent, silver(II) fluoride is often used to synthesize hydrofluorocarbons . In stark contrast to this, all four silver(I) halides are known. The fluoride , chloride , and bromide have the sodium chloride structure, but the iodide has three known stable forms at different temperatures; that at room temperature

2499-470: Is Ag 3 O which behaves as a metallic conductor. Silver(I) sulfide , Ag 2 S, 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 selenides and tellurides are known; in particular, AgTe ~3 is a low-temperature superconductor . The only known dihalide of silver

SECTION 20

#1732772304161

2618-565: Is a type of thin gold medal, usually plain on the reverse, found in Northern Europe from the so-called " Dark Ages " or Migration Period . They often have suspension loops and were clearly intended to be worn on a chain as jewellery. They imitate, at a distance, Roman imperial coins and medallions, but have the heads of gods, animals, or other designs. The Liudhard medalet , produced around AD 600 in Anglo-Saxon England ,

2737-606: Is an isolated example, known from a single copy, of a Christian medal, featuring an inscription naming Liudhard (or "Saint Letard"), the first priest among the Anglo-Saxons, and most likely presented to converts. The surviving example is mounted for wearing as jewellery. In Europe, from the late Middle Ages on, it became common for sovereigns, nobles, and later, intellectuals to commission medals to be given simply as gifts to their political allies to either maintain or gain support of an influential person. The medals were made in

2856-438: Is because its filled 4d shell is not very effective in shielding the electrostatic forces of attraction from the nucleus to the outermost 5s electron, and hence silver is near the bottom of the electrochemical series ( E (Ag /Ag) = +0.799 V). In group 11, silver has the lowest first ionization energy (showing the instability of the 5s orbital), but has higher second and third ionization energies than copper and gold (showing

2975-632: Is bestowed on a member of the United States Armed Forces who distinguishes himself, "conspicuously by gallantry and intrepidity at the risk of his life above and beyond the call of duty while engaged in an action against an enemy of the United States." Each of the three departments of the American armed forces has a unique picture displayed on a medal, which is in turn displayed upon a star-shaped heraldic badge . The medal of

3094-425: Is delocalized, similarly to copper and gold. Unlike metals with incomplete d-shells, metallic bonds in silver are lacking a covalent character and are relatively weak. This observation explains the low hardness and high ductility of single crystals of silver. Silver has a brilliant, white, metallic luster that can take a high polish , and which is so characteristic that the name of the metal itself has become

3213-410: Is found in the Earth's crust in the pure, free elemental 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 byproduct of copper , gold, lead , and zinc refining . Silver has long been valued as a precious metal . Silver metal is used in many bullion coins , sometimes alongside gold : while it

3332-549: 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). 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 oxide as well as Zintl phases like

3451-478: 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. 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

3570-413: Is much less stable, fuming in moist air and reacting with glass. 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 Ag , produced by oxidation of Ag by ozone, is a very strong oxidising agent, even in acidic solutions: it

3689-410: 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". White silver nitrate , AgNO 3 , is a versatile precursor to many other silver compounds, especially the halides, and is much less sensitive to light. It was once called lunar caustic because silver was called luna by

Medal - Misplaced Pages Continue

3808-424: 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 metal is attacked by strong oxidizers such as potassium permanganate ( KMnO 4 ) and potassium dichromate ( K 2 Cr 2 O 7 ), and in

3927-415: Is rare in the periodic table. The atomic weight is 107.8682(2) u ; this value is very important because of the importance of silver compounds, particularly halides, in gravimetric analysis . Both isotopes of silver are produced in stars via the s-process (slow neutron capture), as well as in supernovas via the r-process (rapid neutron capture). Twenty-eight radioisotopes have been characterized,

4046-536: Is reflected in the relative decomposition temperatures of AgMe (−50 °C) and CuMe (−15 °C) as well as those of PhAg (74 °C) and PhCu (100 °C). The C–Ag bond is stabilized by perfluoroalkyl ligands, for example in AgCF(CF 3 ) 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,

4165-430: Is similar in its physical and chemical properties to its two vertical neighbours in group 11 of the periodic table : copper , and gold . Its 47 electrons are arranged in the configuration [Kr]4d 5s , similarly to copper ([Ar]3d 4s ) and gold ([Xe]4f 5d 6s ); group 11 is one of the few groups in the d-block which has a completely consistent set of electron configurations. This distinctive electron configuration, with

4284-472: Is stabilized in phosphoric acid due to complex formation. Peroxodisulfate oxidation is generally necessary to give the more stable complexes with heterocyclic amines , such as [Ag(py) 4 ] and [Ag(bipy) 2 ] : these are stable provided the counterion cannot reduce the silver back to the +1 oxidation state. [AgF 4 ] is also known in its violet barium salt, as are some silver(II) complexes with N - or O -donor ligands such as pyridine carboxylates. By far

4403-593: Is still active, it is for practical purposes inactive, not having been awarded since 1915. The next oldest is the Austro-Hungarian Tapferkeits Medaille Honour Medal for Bravery 1789–1792. This medal was instituted on 19 July 1789, by the Emperor Joseph II. Another of the oldest military decorations still in use is Poland's War Order of Virtuti Militari ( Latin for 'For Military Valour'). It

4522-460: Is termed the obverse, and may contain a portrait, pictorial scene, or other image along with an inscription. The reverse, or back surface of the medal, is not always used and may be left blank or may contain a secondary design. It is not uncommon to find only an artistic rendering on the obverse, while all details and other information for the medal are inscribed on the reverse. The rim is found only occasionally employed to display an inscription such as

4641-413: 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

4760-726: Is used in vacuum brazing . The two metals are completely miscible as liquids but not as solids; their importance in industry comes from the fact that their properties tend to be suitable over a wide range of variation in silver and copper concentration, although most useful alloys tend to be richer in silver than the eutectic mixture (71.9% silver and 28.1% copper by weight, and 60.1% silver and 28.1% copper by atom). 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

4879-482: Is usually obtained by reacting silver or silver monofluoride with the strongest known oxidizing agent, krypton difluoride . Silver and gold have rather low chemical affinities for oxygen, lower than copper, and it is therefore expected that silver oxides are thermally quite unstable. Soluble silver(I) salts precipitate dark-brown silver(I) oxide , Ag 2 O, upon the addition of alkali. (The hydroxide AgOH exists only in solution; otherwise it spontaneously decomposes to

Medal - Misplaced Pages Continue

4998-587: The 1904 Summer Olympics . At the 1896 event, silver was awarded to winners and bronze to runners-up, while at 1900 other prizes were given, not medals. The medals for the London 2012 Summer Olympics are the largest ever, reflecting a trend for increasing size in Olympic medals. The first well-known great artist to create medals was the Italian painter Antonio Pisano, also known as Pisanello , who modelled and cast

5117-472: The Exonumia subcategory of Numismatics , while Orders, Decorations, and Medals are considered Militaria (military related). The Nobel Foundation, the organization awarding the prestigious Nobel Prize , presents each winner, "an assignment for the amount of the prize, a diploma, and a gold medal..." This medal would be displayed framed like a picture, on a table, wall or in a cabinet, rather than be worn by

5236-454: The Greek μέταλλον ( metallon ), "a mine". Traditionally medals are stamped with dies on a durable metal flan or planchet, or cast from a mould . The imagery, which usually includes lettering, is typically in low relief , albeit often higher than on coins: Limited-edition medals may be struck in repeated impacts allowing more metal displacement than in coins produced for mass circulation in

5355-848: The Koenigs–Knorr reaction . In the Fétizon oxidation , silver carbonate on celite acts as an oxidising agent to form lactones from diols . It is also employed to convert alkyl bromides into alcohols . Silver fulminate , AgCNO, a powerful, touch-sensitive explosive used in percussion caps , is made by reaction of silver metal with nitric acid in the presence of ethanol . Other dangerously explosive silver compounds are silver azide , AgN 3 , formed by reaction of silver nitrate with sodium azide , and silver acetylide , Ag 2 C 2 , formed when silver reacts with acetylene gas in ammonia solution. In its most characteristic reaction, silver azide decomposes explosively, releasing nitrogen gas: given

5474-545: 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

5593-632: The Order of the Golden Collar while the New Kingdom awarded the Order of the Golden Fly . Celts and Romans wore a torc or received other military decorations such as the hasta pura , a spear without a tip. Dayaks wore and still wear tattoos , etc. Necklaces and bracelets were given during the early Middle Ages , evolving into large, richly jewelled necklaces, often with

5712-606: The Prussian Iron Cross from 1813. Medals were not awarded to all combatants in a war or battle until the 19th century, when the Waterloo Medal was the first British medal given to all present, at the Battle of Waterloo and all associated actions in 1815. By the middle of the 19th century, the number of awards used had greatly expanded in most countries to something near modern levels. An order tends to be

5831-467: The U.S. Army depicts the head of Minerva , the U.S. Navy medal shows a scene of Minerva doing battle with Discord, and the U.S. Air Force depicts the Statue of Liberty upon its medal. Military decorations, including medals and orders, are usually presented to the recipient in a formal ceremony. Medals are normally worn on more formal occasions and are suspended from a ribbon of the medal's colours on

5950-666: The mythical realm of fairies . 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

6069-435: The platinum complexes (though they are formed more readily than those of the analogous gold complexes): they are also quite unsymmetrical, showing the weak π bonding in group 11. Ag–C σ bonds may also be formed by silver(I), like copper(I) and gold(I), but the simple alkyls and aryls of silver(I) are even less stable than those of copper(I) (which tend to explode under ambient conditions). For example, poor thermal stability

SECTION 50

#1732772304161

6188-526: The post-transition metals . Unlike the preceding transition metals, the +1 oxidation state of silver is stable even in the absence of π-acceptor ligands . Silver does not react with air, even at red heat, and thus was considered by alchemists 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

6307-481: The service ribbons are normally worn on everyday occasions (as opposed to the actual medals). Silver Silver is a chemical element ; it has symbol Ag (from Latin argentum  'silver', derived from Proto-Indo-European *h₂erǵ ' shiny, white ' ) and atomic number 47. A soft, white, lustrous transition metal , it exhibits the highest electrical conductivity , thermal conductivity , and reflectivity of any metal . Silver

6426-464: The 16th century, the wearing of smaller medals on a chain was a persistent fashion for both sexes, and a variety of medals were produced commercially for the purpose, commemorating persons or events, or just with non-specific suitable sentiments. German artists had been producing high-quality medals from the beginning of the century, while the French and British were slower to produce fine work. However, by

6545-686: The 18th century. Devotional medals became very popular in Catholic countries. Very famous is the Miraculous Medal , whose design was created based on the apparitions of the Blessed Virgin Mary to Saint Catherine Labouré in Paris. In 1832, during an epidemic, the first medals were distributed, to which numerous healings and conversions were attributed, receiving the name of Miraculous Medal and distributed to millions of people around

6664-731: 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

6783-598: The British Victoria Cross or American Silver Star), whereas a service award or campaign medal is awarded for serving in a particular capacity in a particular geographical area and time frame (such as the Iraq Campaign Medal). In either case, an award or decoration may be presented as a medal. The Roman Republic adopted an elaborate system of military awards that included medals called phalerae to be issued to soldiers and units for

6902-872: The English-speaking world include Freemasonry , the Orange Order , the Royal Antediluvian Order of Buffaloes , and the Oddfellows . There are also religious fraternal organisations attached to certain Christian denominations (for example, the Catenian Association ), also using medals as jewels of their Orders. Many of these organisations advertise jewels (medals) for sale on their corporate websites. Fraternal jewels may be worn as military-style medals, on ribbons, from

7021-576: The Greek and Roman civilizations, 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 miners produced on

7140-518: The Italian medaglione , meaning "large medal". There are two theories as for the etymology of the word medalia : the first being that the Latin medalia itself is derived from the adjective medialis meaning "medial" or "middle"; the second being that medaglia comes from the Vulgar Latin metallea (moneta) , meaning "metal (coin)" and that from Latin metallum , which is the latinisation of

7259-512: The Renaissance and Mannerist periods were often made for purely decorative purposes, with often crowded scenes from religious, historical or mythological sources. While usually metal, table medals have been issued in wood, plastic, fibre, and other compositions. The US Government awards gold medals on important occasions, with bronze copies available for public sale. Amongst the many fraternal organisations which wear ceremonial regalia ,

SECTION 60

#1732772304161

7378-449: The US, 13540 tons of silver were used for the electromagnets in calutrons for enriching uranium , mainly because of the wartime shortage of copper. Silver readily forms alloys 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

7497-782: The US, Canada, and England produced much high quality work. Military awards and decorations Military awards and decorations are distinctions given as a mark of honor for military heroism , meritorious or outstanding service or achievement. A decoration is often a medal consisting of a ribbon and a medallion. Civil decorations awarded to military personnel should not be considered military decorations, although some orders of chivalry have civil and military divisions. Decorations received by police and fire brigade personnel may sometimes be considered alongside military decorations, on which they may be modelled, although they are strictly not military awards. Decorations have been known since ancient times. The Egyptian Old Kingdom had

7616-452: The aforementioned century, David d'Angers produced a great series of portrait medals of famous contemporaries and in the latter part of the century, Jules-Clément Chaplain and Louis-Oscar Roty were among many highly regarded medalists. The early twentieth century saw art medals flourish, particularly in France, Italy, and Belgium, while later in the century Czechoslovakia, Hungary, Poland,

7735-449: The ample availability. However, a wide range of other media have also been used. Rarer metals have been employed, such as silver , platinum , and gold , when wishing to add value beyond the mere artistic depiction, as well as base metals and alloys such as copper , brass , iron , aluminum , lead , zinc , nickel , and pewter . Medals that are made with inexpensive material might be gilded , silver-plated , chased , or finished in

7854-557: The ancient alchemists, who believed that silver was associated with the Moon. It is often used for gravimetric analysis, exploiting the insolubility of the heavier silver halides which it is a common precursor to. Silver nitrate is used in many ways in organic synthesis , e.g. for deprotection and oxidations. Ag binds alkenes reversibly, and silver nitrate has been used to separate mixtures of alkenes by selective absorption. The resulting adduct can be decomposed with ammonia to release

7973-637: The black silver sulfide (copper forms the green sulfate instead, while gold does not react). While silver is not attacked by non-oxidizing 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 . 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

8092-427: The brooch pin is affixed. Top bars may be hidden under the ribbon so they are not visible, be a plain device from which the ribbon attaches, or may even be decorative to complement the design on the medal. Some top bars are elaborate and contain a whole design unto themselves. Bronze has been the most common material used to create medals, due to its fair price range, durability, ease with which to work when casting, and

8211-712: 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. Silver plays a certain role in mythology and has found various usage as a metaphor and in folklore. The Greek poet Hesiod 's Works and Days (lines 109–201) lists different ages of man named after metals like gold, silver, bronze and iron to account for successive ages of humanity. Ovid 's Metamorphoses contains another retelling of

8330-498: The civil Order of the British Empire . The practice of conferring orders originates with the mediaeval fraternities of knighthood , some of which still exist and are still awarded. While most modern orders have no roots in knighthood, they still tend to carry over the terms of their historic counterparts, and terms such as knight, commander, officer, members, and so on are still commonly found as ranks. A military order may use

8449-434: 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

8568-408: 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). Naturally occurring silver is composed of two stable isotopes , Ag and Ag, with Ag being slightly more abundant (51.839% natural abundance ). This almost equal abundance

8687-411: The elements in groups 10–14 (except boron and carbon ) have very complex Ag–M phase diagrams and form the most commercially important alloys; and the remaining elements on the periodic table have no consistency in their Ag–M phase diagrams. By far the most important such alloys are those with copper: most silver used for coinage and jewellery is in reality a silver–copper alloy, and the eutectic mixture

8806-529: The exceptions are the nitrate, perchlorate, and fluoride. The tetracoordinate tetrahedral aqueous ion [Ag(H 2 O) 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(NH 3 ) 2 ] ; silver salts are dissolved in photography due to the formation of the thiosulfate complex [Ag(S 2 O 3 ) 2 ] ; and cyanide extraction for silver (and gold) works by

8925-433: The extravagant French prince Jean, Duc de Berry , who commissioned a number of large classicising medals that were probably produced in very small numbers, or a unique cast. Only casts in bronze from the originals in precious metal survive, although it is known that at least some medals were also set with jewels, and these may well have been worn on a chain. At the same period, the first known post-classical medal commemorating

9044-422: The filled d subshell, as such interactions (which occur in the preceding transition metals) lower electron mobility. The thermal conductivity of silver is among the highest of all materials, although the thermal conductivity of carbon (in the diamond allotrope ) and superfluid helium-4 are higher. The electrical conductivity of silver is the highest of all metals, greater even than copper. Silver also has

9163-534: 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 analytical 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: The process

9282-523: 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 sp - hybridized sulfur atom. Chelating ligands 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 ] . Under standard conditions, silver does not form simple carbonyls, due to

9401-412: The free alkene. Yellow silver carbonate , Ag 2 CO 3 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: Silver carbonate is also used as a reagent in organic synthesis such as

9520-573: 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 nuclear reactors because of its high thermal neutron capture cross-section , good conduction of heat, mechanical stability, and resistance to corrosion in hot water. The word silver appears in Old English in various spellings, such as seolfor and siolfor . It

9639-514: 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 center." 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

9758-732: The historian Josephus who, writing long after the event, accounts that in the second century BCE , the High Priest Jonathan led the Hebrews in aid of Alexander Balas , and that in return for this, Alexander "...sent to Jonathan... honorary awards, as a golden button, which it is custom to give the king's kinsmen." Roman emperors used both military awards of medals, and political gifts of medallions that were like very large coins, usually in gold or silver, and die-struck like coins. Both these and actual golden coins were often set as pieces of jewellery, worn by both sexes. The bracteate

9877-636: The hobby. Traditionally, medals are made of the following metals, in order of decreasing value: Many medals were and are made in several different metals, either representing awards for different places in a competition, or standards or classes, as with the Olympic medals , or simply different price levels for medals made for sale or donation by the commissioner. Medals have historically been given as prizes in various types of competitive activities, especially athletics. The gold, silver and bronze Olympic medals for first, second and third places were first used at

9996-580: The humanists began to make their own medals, normally in bronze, to send to their patrons and peers. The fashion remained restricted to Italy until near the end of the 15th century, when it spread to other countries. By the 16th century, medals were increasingly produced by rulers or cities for propaganda purposes. In 1550, a die-stamping machine, using steel dies, was introduced in Augsburg , Germany, and soon this process became standard. The artist now cut an intaglio die rather than modelling in relief . By

10115-532: The late 17th century, most parts of Western Europe could produce fine work. Some medals were also collected, which continues to the present day. Official medals, from which specialized military awards descended, were increasingly produced, but the real growth in military medals did not come until the 19th century. In the East, a wide variety of medals and decorations have been given by the Ottoman Empire since

10234-443: The left breast, or more prominently on collars or collarettes as part of the organisation's regalia. Historic examples of such medals and jewels may be found in many museums, particularly museums dedicated to fraternal organisations. There is extensive trade in fraternal jewels and medals, with societies and associations existing to promote such trade, and to encourage the sharing of resources, and on-line resources available to support

10353-681: The left breast, while a corresponding ribbon bar is to be worn to common events where medals would be inappropriate or impractical to wear. Medallion is a vague term, often used for larger, usually circular, medals, which might be worn as pendants round the neck. It is the correct term for such medals from the late Roman Empire , typically distributed by the emperor and bearing his image, but in later periods larger medals are best termed just as medals. Generally circular, table medals are issued for artistic, commemoration, or souvenir purposes, not for commerce, and are too large to be plausibly worn. Tokens and Table Medals of coin-like appearance are part of

10472-407: 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 currents tend to flow on the surface of conductors rather than through the interior. During World War II in

10591-618: The metal. 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 , these techniques did not spread widely until later, when it spread throughout

10710-482: The most elaborate of military decorations, typically awarded for distinguished services to a nation or to the general betterment of humanity. Orders are distinguished from other forms of decoration in that they often imply membership in an organization or association of others that have received the same award. Two of the most well known and commonly awarded orders are the Légion d'honneur of France (military and civil) and

10829-434: 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 polarized 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:

10948-546: The most stable being Ag with a half-life of 41.29 days, Ag with a half-life of 7.45 days, and Ag with a half-life of 3.13 hours. Silver has numerous nuclear isomers , the most stable being Ag ( t 1/2 = 418 years), Ag ( t 1/2 = 249.79 days) and Ag ( t 1/2 = 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 relative atomic mass from 92.950 u ( Ag) to 129.950 u ( Ag);

11067-588: The only objects with a high-enough palladium-to-silver ratio to yield measurable variations in Ag abundance. Radiogenic Ag was first discovered in the Santa Clara meteorite in 1978. Pd– Ag 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. Silver is a rather unreactive metal. This

11186-625: 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 (Australia), Fresnillo (Mexico), San Cristóbal (Bolivia), Antamina (Peru), Rudna (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

11305-423: The oxide.) Silver(I) oxide is very easily reduced to metallic silver, and decomposes to silver and oxygen above 160 °C. This and other silver(I) compounds may be oxidized by the strong oxidizing agent peroxodisulfate to black AgO, a mixed silver(I,III) oxide of formula Ag Ag O 2 . Some other mixed oxides with silver in non-integral oxidation states, namely Ag 2 O 3 and Ag 3 O 4 , are also known, as

11424-405: The past, medals commissioned for an individual, typically with their portrait, were often used as a form of diplomatic or personal gift, with no sense of being an award for the conduct of the recipient. An artist who creates medals or medallions is called a " medalist ". Medals have long been popular collectible items, and in numismatics form a class called either exonumia or militaria . In

11543-577: The photosensitivity of silver salts, this behaviour may be induced by shining a light on its crystals. Silver complexes tend to be similar to those of its lighter homologue copper. Silver(III) complexes tend to be rare and very easily reduced to the more stable lower oxidation states, though they are slightly more stable than those of copper(III). For instance, the square planar periodate [Ag(IO 5 OH) 2 ] and tellurate [Ag{TeO 4 (OH) 2 } 2 ] complexes may be prepared by oxidising silver(I) with alkaline peroxodisulfate . The yellow diamagnetic [AgF 4 ]

11662-961: The presence of potassium bromide ( KBr ). 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 oxidation states of silver are (in order of commonness): +1 (the most stable state; for example, silver nitrate , AgNO 3 ); +2 (highly oxidising; for example, silver(II) fluoride , AgF 2 ); and even very rarely +3 (extreme oxidising; for example, potassium tetrafluoroargentate(III), KAgF 4 ). 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. Indeed, silver(III) fluoride

11781-406: The primary decay mode before the most abundant stable isotope, Ag, is electron capture and the primary mode after is beta decay . The primary decay products before Ag are palladium (element 46) isotopes, and the primary products after are cadmium (element 48) isotopes. The palladium isotope Pd decays by beta emission to Ag with a half-life of 6.5 million years. Iron meteorites are

11900-472: The proper use of the term, medallions are larger, starting at perhaps four inches across, and are, as such, usually too large to be worn very comfortably, though in colloquial use, "medallion" is often used to refer to a medal used as the pendant of a necklace (as in the medallion man fashion style of the 1960s and 1970s), or for other types of medals. Medallions may also be called "table medals" because they are too large to be worn and can only be displayed on

12019-419: The reaction of the bis(NHC)silver(I) complex with bis(acetonitrile)palladium dichloride or chlorido(dimethyl sulfide)gold(I) : Silver forms alloys with most other elements on the periodic table. The elements from groups 1–3, except for hydrogen , lithium , and beryllium , are very miscible with silver in the condensed phase and form intermetallic compounds; those from groups 4–9 are only poorly miscible;

12138-512: 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 Phoenicians 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

12257-701: The same as that of mercury . It mostly occurs in sulfide ores, especially acanthite and argentite , Ag 2 S. Argentite deposits sometimes also contain native silver when they occur in reducing environments, and when in contact with salt water they are converted to chlorargyrite (including horn silver ), AgCl, which is prevalent in Chile and New South Wales . Most other silver minerals are silver pnictides or chalcogenides ; they are generally lustrous semiconductors. Most true silver deposits, as opposed to argentiferous deposits of other metals, came from Tertiary period vulcanism. The principal sources of silver are

12376-693: 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. 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 ,

12495-422: The stability of the 4d orbitals), so that the chemistry of silver is predominantly that of the +1 oxidation state, reflecting the increasingly limited range of oxidation states along the transition series as the d-orbitals fill and stabilize. Unlike copper , for which the larger hydration energy of Cu as compared to Cu is the reason why the former is the more stable in aqueous solution and solids despite lacking

12614-445: The stable filled d-subshell of the latter, with silver this effect is swamped by its larger second ionisation energy. Hence, Ag is the stable species in aqueous solution and solids, with Ag being much less stable as it oxidizes water. Most silver compounds have significant covalent character due to the small size and high first ionization energy (730.8 kJ/mol) of silver. Furthermore, silver's Pauling electronegativity of 1.93

12733-411: The story, containing an illustration of silver's metaphorical use of signifying the second-best in a series, better than bronze but worse than gold: But when good Saturn , banish'd from above, Was driv'n to Hell, the world was under Jove . Succeeding times a silver age behold, Excelling brass, but more excell'd by gold. In folklore, silver was commonly thought to have mystic powers: for example,

12852-502: The term " silverware "), in electrical contacts and conductors , in specialized mirrors, window coatings, in catalysis of chemical reactions, as a colorant in stained glass , and in specialized confectionery. Its compounds are used in photographic and X-ray film. Dilute solutions of silver nitrate and other silver compounds are used as disinfectants and microbiocides ( oligodynamic effect ), added to bandages , wound-dressings, catheters , and other medical instruments . Silver

12971-411: The use of medals is commonplace. In many prominent fraternal organisations, fraternal medals are known as jewels . Their purpose varies, and may include use as a badge of membership, an indication of rank, a symbol of office within the fraternity, or an indication of support having been given to a designated charitable cause (so-called charity jewels ). Common secular fraternities using jewels (medals) in

13090-458: The weakness of the Ag–C bond. A few are known at very low temperatures around 6–15 K, such as the green, planar paramagnetic Ag(CO) 3 , which dimerizes at 25–30 K, probably by forming Ag–Ag bonds. Additionally, the silver carbonyl [Ag(CO)] [B(OTeF 5 ) 4 ] is known. Polymeric AgLX complexes with alkenes and alkynes are known, but their bonds are thermodynamically weaker than even those of

13209-630: The winner. The Carnegie Hero Foundation is the issuer of a bravery medal, most commonly issued in the US, Canada, and the UK. This large bronze table medal features Andrew Carnegie's likeness on the obverse and the name of the awardee and citation engraved on the reverse. It is usually issued for lifesaving incidents. In the U.S. Military , challenge coins are a type of relatively unofficial medal given to boost morale, and sometimes to act as convenient passes for unit members. Also related are plaques and plaquettes , which may be commemorative, but especially in

13328-499: 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 civilizations 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

13447-575: The world. During the Reformation there had also been a vigorous tradition of Protestant medals, more polemical than devotional, which continued with the Geuzen medals produced in the Dutch Revolt . Military decorations , service awards, and medals are often mistakenly confused with one another. Decoration is a term for awards which require specific acts of heroism or achievement (such as

13566-413: 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 thirty pieces of silver , referring to

13685-457: Was cast rather than die-struck. With each successive cast the medal became slightly smaller, and the numbers that could be produced were probably not large. A lead "proof" was probably often used. The association between medals and the classical revival began to take a rather different form, and the exchange of medals became associated with Renaissance Humanism . Princes would send humanist writers and scholars medals in recognition of their work, and

13804-502: Was established, and mostly awarded to non-officers. The Légion d'honneur instituted by Napoleon I in 1802 had some of the characteristics of the old military orders, but was intended to be far more inclusive, and was awarded to rank and file soldiers for bravery or exceptional service. Other nations followed with decorations such as the British Army Gold Medal from 1810, though this only went to senior officers, and

13923-424: Was first awarded in 1792. Medals have been forged by many people to make the medal appear more valuable or to make one look like a more decorated soldier. Medal forgeries can include: adding bars , engraving a famous soldier's name on it or creating a whole new medal. Medal forgery is illegal in most countries and can be punishable by imprisonment. Today military decorations include: In most NATO militaries, only

14042-510: Was more often used ornamentally or as money. Since silver is more reactive than gold, supplies of native silver were much more limited than those of gold. For example, silver was more expensive than gold in Egypt until around the fifteenth century BC: the Egyptians are thought to have separated gold from silver by heating the metals with salt, and then reducing the silver chloride produced to

14161-457: Was the usual Proto-Indo-European word for the metal, whose reflexes are missing in Germanic and Balto-Slavic. Silver was known in prehistoric times: the three metals of group 11, copper, silver, and gold, occur in the elemental form in nature and were probably used as the first primitive forms of money as opposed to simple bartering. Unlike copper, silver did not lead to the growth of metallurgy , on account of its low structural strength; it

#160839