Silver

characteristics
palladium - silver - cadmium
cu
AG
outer one

[Kr] 4d 10 5s 1
,107
47
AG

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generally
name, symbol, ordinal number silver, AG, 47
series Transition metals
group, period, block 11, 5, D
appearance silvery
proportion at the Earth's shell 1 · 10 -5 %
atomically
atomic mass 107.8682 u
atomic radius (computed) 160 (165) pm
Kovalenter radius 153 pm
van the Waals radius 172 pm
Elektronenkonfiguration [Kr] 4d 10 5 s 1
electrons per energy level 2, 8, 18, 18, 1
1. Ionization energy 731.0 kJ/mol
2. Ionization energy 2070 kJ/mol
3. Ionization energy 3361 kJ/mol
physically
state of aggregation firmly
crystal structure cubically face-centered
modifications -
density (Mohshärte) 10490 kg/m 3 (2,5)
magnetism -
melting point 1234.93 K (961.78 ° C)
boiling point 2435 K (2162 °C)
molecular volume 10,27 · 10 -6 m 3 /mol
heat of vaporization 250.58 kJ/mol
heat of fusion 11.3 kJ/mol
steam pressure 0.34 Pa at 1234 K
speed of sound 2600 m/s with 293,15 K
specific thermal capacity 232 j (kg · K)
Electrical conductivity 62 · 10 6 S /m
heat conductivity 429 w (m · K)
Electron affinity of 4.3 eV
chemically
oxidation conditions of +1, +2
oxides (basicity) AG 2 O (more amphoter), AgO
normal potential 0.7996 V (AG + + e - → AG)
Elektronegativität 1.93 (Pauling scale)
isotopes
isotope NH t 1/2 ZM CPU M eV ZP
105 AG {syn.} 41.29 D ε 1.346 105 Pd
106 AG {syn.} 23.96 min ε
β -
2.965
0.195
106 Pd
106 CD
106 m AG {syn.} 8.28 D ε
IT
3.055
0.090
106 Pd
106 AG
107 AG 51.839% AG is stable with 60 neutrons
108 AG {syn.} 2.37 min β -
ε
1.649
1.918
108 CD
108 Pd
108 m AG {syn.} 418 A ε
IT
2.027
0.109
108 Pd
108 AG
109 AG 48.161% AG is stable with 62 neutrons
110 AG {syn.} 24.6 s β -
ε
2.892
0.893
110 CD
110 Pd
110 m AG {syn.} 249.79 D β -
IT
3.010
0.118
110 CD
110 AG
111 AG {syn.} 7.45 D β - 1.037 111 CD
NMR characteristics
107 AG 109 AG
nuclear spin 1/2 1/2
gamma/ wheel/T 1,082 · 10 7 1,244 · 10 7
sensitivity 6,62 · 10 -5 0.000101
Larmorfrequenz with B = 4.7 T 8.09 M cycles per second of 9.3 M cycles per second
as far as possible and common, are used SI-UNITs.
If notdifferently noted,
the indicated data apply with standard conditions.

Silver is a chemical element. It belongs to the Münzmetallen. The German word silver comes from the old-high-German word Silabar, which possibly decreases/goes back on Homers legend country Salybe.

Silver is inPrecious metal and chemical element from the first Nebengruppe (group of copper) of the periodic system. The element symbol AG is derived from latin word A r g entum „silver “. It is beside copper one of two elements, which name giver for a country is (Silver for Argentina and copper for Cyprus). It is a soft and well ductile heavy metal and possesses the largest electrical conductivity of all elements.

Table of contents

silver as mineral

silver stage, approx.: 5x3 cm

silver is found gediegen in nature. The radiate-white metal crystallizes incubic-face-centered crystal system (English cubic closed package - ccp) and has a metallic gloss. Polished silver shows the highest light reflection characteristics of all metals, freshly separated silver reflected over 99,5% of the visible light. As „the whitest of “all customs metals it becomes therefore alsoProduction of mirrors uses. The surface of the silver is usually colored line color by oxides and sulfides brown to violet, is a gräuliches white. With removing grain size the color becomes ever darker and is black with photographically finely distributed silver crystals. ThatFine metal is a outstanding leader for electricity and warmth. With a hardness from 2,5 to 3 silver is besides a soft metal, an only little harder as Feingold and somewhat softer than copper: A gram leaves itself to two kilometerslong thread pull.

The component at the earth's crust is small with approximately 0.079 ppm (according to 0.0000079 per cent).

promotion

Gediegenes silver appears usually in the form of grains or as network in Hydrothermaladern, drahtig branched out. Most silverbecomes however from Silbererzen, which often together with lead, copper and Zinkerzen as sulfides or oxides to occur, won.

Silbererze:

with the production of silver is used sodium cyanide, which leads to the formation of silver-containing complexes,in a following electrolysis (Möbiusverfahren) to the pure silver lead. Considerable silver quantities result also with the refining of the mass metals copper, lead and zinc, whose production has so also influence on the silver offer of the world markets. Silver fallsalso as Beimetall with the production of other precious metals on.

As is the case for the other precious metals the reprocessing of silver-containing materials plays an important role in the context of the recycling of for example photo papers, radiographic films, developer and fixing baths , electronics materials and batteries.

The largestSilver producers are Mexico, Peru, and Australia (conditions 2004). The history of the Bolivian city Potosí is completely particularly coined/shaped by the silver dismantling and the consequences for the there mine workers. About 6500 children and young person work there also today stillin the silver mining industry.

The largest promotion nations world-wide (2003)
source: Trade paper the world in figures (2005)
rank country deliveries
(in t)
rank country deliveries
(in t)
1 Mexico 2955 11 Turkey 795
2 Peru 2921 12 Bolivia 455
3 Australia 2056 13 Sweden 300
4 Poland 1561 14 Morocco 240
5 Canada 1255 15 Indonesia 166
The 6 USA 1239 16 Argentina 134
7 China 1200 17 South Africa 130
8 Chile 1100 18 Japan 82
9 Russian Föd. 810 19 Greece 79
10 Kazakhstan 800 20 Papua New Guinea 60

use

silver one uses for centuries for erlesene and Essbestecke, board silver of stable value and church devices. In addition, silver is particularly suitable for decoration, became in the form of silver coins asCurrency assigned. Silver bars are used like gold and platinum ingots as bank reserves. With decoration and ingot the Silbergehalt can be read off to the Repunze.

Silver possesses a high electrical conductivity, a high heat conductivity and a pronounced optical reflection ability. Thusit is suited for applications in electrical connection , electronics and optics. The reflection ability of glass mirrors is based on the chemical silver plating of windowpanes, and this principle is used about also with Christian tree decoration, optics and light or heat reflectors. The density of the Silbersalzewith the photo paper and forms since approximately 1850 the basis of photochemistry is used by light.

Silver alloys (with copper, zinc, tin, nickel, Indium, etc.) become in electro-technology and thermodynamics as plumb bob alloys (so-called braze welding), contact contacts and guidance material uses. In addition, silver alloys are used in the dental technology and within the decorative range.

Silver is used as food coloring material E 174 also within the food range, for example for coats of sweet goods as for instance chocolates and in Likören. Silbersalze color glass and enamel yellow.


silver alloy

the today most common silver alloys have a fineness of 800/1000, 835/1000, 925/1000 (Sterlingsilber) and 935/1000 parts silver, alloyed with another metal, usually copper for strength increase. In view upthe export today Korpuswaren predominantly of a silver alloy with a fineness of 935/1000 made, since the goods with silver plumb bobs are soldered, their fineness lower is, in order to finally meet the legally demanded total fineness from for example 925/1000 to. Also with strongthe trend goes to stressed cutleries to the Sterlingsilber for years. A new alloy from England is Argentium Sterling silver, which is not to start. German silver is against it no silver, but a silver-similar, white Unedelmetalllegierung from cupro-nickel zinc. Silver goods become in thatRule finally fine-silvered, cutleries and wear articles hardsilvers. The salespromoting radiate-white silver color and strongly decreased starting of the goods are reached by the pure silver coating.

Silver is gilded frequently also, one calls it with from the French and/or latin a comingWord then Vermeil.

chemical characteristics

silver is relatively poorly reactive as precious metal. At normal air its surface approaches however with the time, black on in particular by reaction with hydrogen sulfide H 2 S, that the elementary silver Silbersulfid (AG 2 S) oxidizes:

4 AG + 2 H 2 S + O 2 → 2 AG 2 S + 2 H 2 O

light, higher temperatures, humidity, sulfur-pure and oxygen accelerates this process.

Silver is with mostMetallic one alloyable. Well to alloy it leaves itself also to gold or palladium (a palladium content from 20 to 30 per cent the silver makes approach steady). To limited extent the silver with chrome , manganese or nickel can be alloyed. It does not leave itselfalloy with cobalt or iron.

Silver is bactericidal, thus weakly toxic in purify-distributed form, which is to be attributed due to the large reactive surface to the sufficient emergence soluble silver ions. In the living organism silver ions become however usually fastbound at sulfur and separate from the material cycle as dark, with difficulty soluble Silbersulfid .

Silbergeschirre and devices deliver something silver with the use always also to the meals and beverages, which becomes apparent in the unpleasant metal taste. Around thisto prevent and around the cleaning simplify, silver drinking containers are inside gilded.

In most connections silver in the Oxidationsstufe +1 is present, in addition, there are the Oxidationsstufen +2, as for example in the Tetrapyridinosilber (II) - by sulfate - [AG (C 5 H 5N) 4] S 2 O 8 - or in the silver (II) - fluoride, and +3, as in the Kaliumtetrafluoroargentat (III) - K [AgF 4].

Silbersalze are usually colorless. Typical connections are the salts Silberchlorid (AgCl), Silberbromid (AgBr) and silver nitrate (AgNO 3). Ofthe salts silver (I) the halides are heavy, with exception of the silver fluoride (AgF), and the sulfide (AG 2 S) in water and acids to insoluble. Well solubly however nitrate ( AgNO 3) is, chlorate (AgClO 3), Perchlorat (AgClO4) and fluoride (AgF); are moderately soluble sulfate (AG 2 SO 4), acetate (CH 3 COOAg) and nitrite (AgNO 2).

As precious metal silver separates only in oxidizing acids, as for example concentrated nitric acid (HNO 3)or hot concentrated sulfuric acid (H 2 SO 4):

<math> \ mathsf {3 \ AG \ + \ 4 \ H^+ \ + \ 4 \ NO_3^ \ longrightarrow 3 \ Ag^+ \ + \ 3 \ NO_3^ \ + \ NO \ uparrow + \ 2 \ H_2O}< /math>
<math> \ mathsf {2 \ AG \ + \ 4 \ H^+ \ + \ 2 \ SO_4^ {2} \ longrightarrow 2 \ Ag^+ \ + \SO_4^ {2} \ + \ SO_2 \ uparrow + \ 2 \ H_2O}< /math>

The poisonous Silbercyanide become and. A. used in galvanic baths to the silver plating and color gold plating (lightyellow greenish yellow).

With silver (I) the inclination to the formation of Komplexionen is pronounced, usually with the co-ordination number of 2. These Komplexionen are alsoException of the only in strong salt-sour solution developing [AgCl 2] - only in more alkalinely (more basic) or neutral solution steady.

physical characteristics

silver is a white shining precious metal. The fusing temperature under normal print amounts to 961 °C andthe boiling temperature 2212 °C. Silver has however already above 700 °C, thus still in the solid state, an observable steam pressure. It simmers under formation of monatomic, blue steam. The precious metal possesses a density of 10,49 g/cm ³ (with 20 °C) andheard therefore it like all precious metals to the heavy metals. It possesses a hardness after Mohs of 2,5. It leads the warmth and the electricity best from all metals and leaves themselves because of its elasticity and softness to finest, cyan through-resplendent foilshammer out from a thickness from only 0.002 to 0.003 millimeters or to thin, with 2 kilometers length only 0.1 to 1 gram weighing wires (Filigrandraht) take off.

proof

Silberiodid-Niederschlag in Ammoniak-wasser
silver iodine ID precipitation in ammonia liquors

with the Zutropfen of halide - solution into thoseprecipitation forms liquid which can be examined with the presence of silver ions. So for example during saline solution:

NaCl (aq.) + AgNO 3 (aq.) <math> \ longrightarrow </math> Nano 3 (aq.) + AgCl< math> \ downarrow< /math>

As proof reaction for Silbersalze therefore the addition takes place from hydrochloric acid orSodium chlorid solution: A white precipitation of Silberchlorid (complex solubly with diluted ammonia liquor as ligand, the Silberdiammin develops complex [AG (NH 3) 2] + ).
With high concentrations of chloride - for example from concentrated hydrochloric acid (HCl) -the Silberchlorid also separates, there Dichloroargentat (I) forms:
AgCl + Cl - <math> \ Longleftrightarrow< /math> [AgCl 2] -

the precipitation is with iodine ID ions (AgI) yellow-greenish and in ammonia liquors insolubly, with chloride and bromide ions (AgCl, AgBr) whitish.

Work on []

History

silver becomes of humans for instance since that 5. Millenium v. Chr. processed. It became for example from the Assyrern, the Goten, the Greek, the Romans, whom uses Egyptians and the Teuton. At that time it appliedas more valuable than gold. The silver mostly originated from the mines in Lavrion, which lay about 50 kilometers south of Athens. With the old Egyptians silver was well-known as the moon metal.

In the Middle Ages silver ore occurrences in the resin became in Germany (Goslar), in Saxonia (free mountain and remaining ore mountains), south Black Forest (looking in country, Belchen, field mountain), Böhmen (Kutná Hora) and the Slowakei discovers.

Later the Spaniards accommodated large quantities of silver from America,other one from the sagenumwobenen mine of Potosi, to Europe. Also Japan was in 16. Jh. Silver exporter. By the risen offer the silver value in the old world sank.

Since after 1870 gold was predominantly used as standard metal, the silver lostits economic meaning ever more. The Wertverhältnis was reduced from 1:14 some time long to 1:100, later rose it again somewhat. Today it lies on approximately 1:60. The offer at silver depends on the consumption and production development of other metals.

Center 19. Century stainless steel was developed, which penetrated then due to its customs friendliness and the attractive price into the First World War into the areas of application of the silver, about serving plates, cutleries, Leuchter and kitchen equipment. Moving in opposite directions to it the range photography has itselfand photo chemistry using the Silbersalze during whole 20. Century broadly developed, however meaning loses since end of the 90's in the course of the conversion in the digital illustration technology.

Despite this development the silver oh question is world-wide rising andup-to-date (2006) still by the fact it is covered that some states, for example the People's Republic of China, at present their silver reserves to sell. Since the existence goes to the slope, silver is regarded as underestimated.

silver in the medicine

Silberverbindungen findas disinfectants and as therapeutic agent in the Wundtherapie use. Silver ions can inhibieren silver-sensitive exciters after relatively long impact time reversibly, can in addition bakteriostatisch or even bactericidal (thus killing) to work. One speaks here of the oligodynamischen effect. In some cases chlorine compounds are added,in order to increase the too small effectiveness of the silver alone.

Different effect mechanisms are used:

  • Blocking of enzymes and prevention their vitally necessary transportation functions in the cell
  • impairment of the cell structural strength
  • damage of the diaphragm structure and change of the osmotic equilibrium in thatCell by release the effects described by essential ions such as

sodium and potassium can lead to cell death.

Beside the Argyrie, an irreversible slate-grey discoloration of skin and mucous membranes, it can with increased silver accumulation in the body in addition to taste disturbances, Geruchsempflichkeitas well as cerebral convulsions come.

The therapeutic income is disputed by colloidal silver, for some years again strengthened in the field of vision of the public moves partially highly praised and in the Internet of not respectable offerers and as universal remedies and universalantibiotic is designated. Unfortunately neutral and secured statements about a use of colloidal silver are missing with humans. An indication does not give it therefore.

silver in antibacterial applications

in more recent time materials or coating processes were developed,the antibacterial effect of silver make themselves. With certain procedures usually nanoskaliges silver is embedded into materials. The embedded silver delivers continuously silver ions and works thereby antibacterially. Examples of such applications are:

  • Silver threads or silver ionsrestrain in the antimicrobial equipment of textiles the growth of bacteria on the skin and prevent thereby unpleasant smells.
  • to the achievement of dermatologischer effects, z. B. with Neurodermitis
  • coating of surfaces, z. B. in refrigerators, on kitchen furniture and other articles
  • of plasticsto application in the medical technology
  • antibacterial enamelling
  • antibacterial ceramic(s)

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