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About Silver

Silver Bohr

Silver was one of the first known metals, valued even by ancient civilizations: the naturally-occurring gold-silver alloy electrum was used to make some of the first metal coins. Functional uses of silver have long competed with its use as a precious metal, as its has many useful properties that recommend it for wide-reaching applications, but is often too expensive to use when alternative materials exist. At times the existence of easily accessible silver stockpiles have led to its substitution for cheaper metals that are temporarily in short supply. Most notably, silver reserves were tapped during the world wars, substituting for copper in electrical applications, tin in solder, and nickel in the production of coins.

Traditionally silver has served functions to be expected for a precious metal, playing a large role in monetary systems and been used in ornamental items such as jewelry. Additionally, it was once frequently used for the production finer household wares that serve dual functional and decorative functions including utensils, the latter being the use from which the term “silverware” is derived. Such silver objects are usually salloys rather than pure silver, and the standard “sterling silver”--which is 7.5% copper--remains a popular jewelry making material. Household silver has largely been replaced by other materials, either due to cost or because of the frequent polishing to remove tarnish that silver objects usually require. Silver has also long been used for the production of high-quality wind instruments, either as the solid metal or as a plated coating on cheaper materials.

Several other major uses for silver have histories reaching back to the 19th century or earlier. Mirrors can be produced by a chemical process that coats glass with thin layer of silver metal, often termed silvering, which was discovered in 1835. Today, standard mirrors are usually produced using sputtered thin coats of aluminum as it is cheaper than silver and less subject to tarnishing, but glass ornaments and some high quality mirrors are still sometimes made with the silvering process. Thinner layers of silver are visually transparent but effectively block UV radiation; today glass coated with such layers is used in energy-saving window panes. Film photography was first developed around the same time, and then as now, silver was an essential component of almost all film photography processes, which exploit the photosensitivity of silver halide compounds. Finally, silver ions are naturally germicidal, and silver and its compounds have been used in wound care and as disinfectant for centuries. Today, silver is still found in antimicrobial creams for treating burns, and silver nanoparticles are used in water filtration systems and embedded in clothing to deter bacterial growth.

Silver has the highest electrical conductivity of any element. Copper is used more frequently for electrical wiring as it is more economically viable, but for some applications the energy savings or performance benefits provided by the substitution of silver are substantial enough to overcome this cost barrier. The largest example of this is use in connectors in high quality radio frequency devices, and additionally some manufacturers of audio equipment produce silver connector cables and speaker wires for audiophiles who believe this improves sound quality.

Additionally, silver may be used for electronics applications in cases where other key physical or chemical properties make it uniquely suited for an application. For instance, silver nanowires can be used to produce transparent and flexible electrodes for use in devices such as solar cells, and silver nanoparticles can be used in conductive inks used in the production of RFID tags, as well as in membrane switches used for tv remote controls, computer keyboards, and control panels on home appliances. Silver cadmium oxide and several other conductive silver compounds are favored for use in high-voltage contacts because they resist the effect of electrical arcing. Silver also is a component of some materials used for phase-change memory technologies, such as rewritable optical discs (CD-RW).

Silver also finds use in several specialized battery formulations. As with the use of silver as a conductor for electronics, the use of these batteries are limited by the added expense of silver, but in some applications the advantages are considered worth the cost. Silver oxide batteries have a long working life and high energy-to-weight ratio, and therefore are used in small devices such as hearing aids. Silver-zinc batteries are likewise valued for high-energy density, as well as for being extremely safe and reliable, with a long life both on the shelf and in active use. Silver-zinc formulations are frequently used for batteries designed for aerospace and defense applications, and are found in NASA launch vehicles, missiles, and satellites.

An additional key use for silver is in silver soldering and brazing. Both are methods used to join metallic components, but they vary in the composition of the joining material and the temperatures required. Silver soldering is a lower temperature process often used in jewelry making or as a substitute for lead-based solders, and often uses tin-silver or tin-silver-copper formulations. Silver brazing is a higher temperature process that produces an extremely strong joint that will resist significant shock and vibration while using very small amounts of silver brazing alloy such as . Brazing is used frequently for attaching cemented carbide tips to tools. Cemented carbide is both more expensive and more brittle than other typical tool materials, but its extreme hardness is preferable for machining tough materials such as steels. For this reason, machining equipment frequently uses carbide tips or inserts that can be attached via brazing to a larger tool.

A number of key niche uses for silver also exist. Silver staining procedures, which typically make use of the soluble silver source silver nitrate along with various sensitizers and fixatives, are used in biology labs, as silver ions bind tightly to most proteins, allowing their visualization on diagnostic gels, in karyotypes, and in tissue samples. Silver is often included in nuclear control rods to absorb free neutrons. Silver is often used to plate steel bearings for use in automotive or jet engines, as this results in lower friction. Amalgam fillings made of mercury in combination with silver or gold are still used in dentistry, but increasingly ceramic composites are favored for cosmetic reasons and due to safety concerns related to the use of mercury. Silver is additionally used as a catalyst in the industrial production of ethylene oxide, used to make polyester and antifreeze, and formaldehyde, which is used in adhesives, laminating resins, and protective finishes. Silver may also be one of several catalysts found in catalytic converters which reduce toxic emissions from automobiles, but platinum group metals are usually preferred for this purpose.

Silver can be found as a native metal or as part of natural alloys with gold, but is more often a component of minerals such as argentite. It is most often produced for commercial uses as a byproduct of mining and refining copper, copper-nickel, lead, and lead-zinc ores, which frequently contain some amount of silver minerals.

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High Purity (99.999%) Silver Oxide (AgO)Powder Silver has a long history as a precious metal where it's been used in coins, ornaments, jewelry, and utensils (silverware). Silver is also used for electrical contacts and conductors. It's sometimes used as a catalysis of chemical reactions. Silver nitrate has wide application in painting, xerography, chemical electroplating and electric batteries. Silver chloride is another important compound, due to its ductility and malleability. High Purity (99.999%) Silver (Ag) Sputtering TargetThe organic compounds of the element are used in the coating of several metals and in dynamite or other explosive bars. Silver is available as metal and compounds with purities from 99% to 99.999% (ACS grade to ultra-high purity). Elemental or metallic forms include pellets, rod, wire and granules for evaporation source material purposes. Silver nanoparticles and nanopowders provide ultra-high surface area. Oxides are available in powder and dense pellet form for such uses as optical coating and thin film applications. Oxides tend to be insoluble. Fluorides are another insoluble form for uses in which oxygen is undesirable such as metallurgy, chemical and physical vapor deposition and in some optical coatings. Silver is also available in soluble forms including chlorides, nitrates and acetates. These compounds can be manufactured as solutions at specified stoichiometries.

Silver Properties

Silver(Ag)atomic and molecular weight, atomic number and elemental symbolSilver is a Block D, Group 11, Period 5 element. Silver Bohr ModelThe number of electrons in each of Silver's shells is 2, 8, 18, 18, 1 and its electron configuration is [Kr]4d10 5s1. Elemental SilverThe silver atom has a radius of and its Van der Waals radius is In its elemental form, CAS 7440-22-4, silver has a brilliant white metallic luster. It is a little harder than gold and is very ductile and malleable, being exceeded only by gold and perhaps palladium. Pure silver has the highest electrical and thermal conductivity of all metals, and possesses the lowest contact resistance. It is stable in pure air and water, but tarnishes when exposed to ozone, hydrogen sulfide, or air containing sulfur. Silver was first used by early humans, begininng prior to 5000 BC. It is found in copper, copper-nickel, lead, and lead-zinc ores among others. Silver was named after the Anglo-Saxon word "seolfor" or "siolfur" meaning 'silver'.

Symbol: Ag
Atomic Number: 47
Atomic Weight: 107.8682
Element Category: transition metal
Group, Period, Block: 11, 5, d
Color: silver
Other Names: Argentum, Argent, Silber, Plata
Melting Point: 961.78 °C, 1763.2 °F, 1234.93 K
Boiling Point: 2162 °C, 3924 °F, 2435 K
Density: 10.49 g·cm3
Liquid Density @ Melting Point: 9.320 g·cm3
Density @ 20°C: 10.5 g/cm3
Density of Solid: 10490 kg·m3
Specific Heat: 0.23 (kJ/kg/K)
Superconductivity Temperature: N/A
Triple Point: N/A
Critical Point: N/A
Heat of Fusion (kJ·mol-1): 11.3
Heat of Vaporization (kJ·mol-1): 257.7
Heat of Atomization (kJ·mol-1): 284.09
Thermal Conductivity: 429 W·m-1·K-1
Thermal Expansion: (25 °C) 18.9 µm·m-1·K-1
Electrical Resistivity: (20 °C) 15.87 nΩ·m
Tensile Strength: N/A
Molar Heat Capacity: 25.350 J·mol-1·K-1
Young's Modulus: 83 GPa
Shear Modulus: 30 GPa
Bulk Modulus: 100 GPa
Poisson Ratio: 0.37
Mohs Hardness: 2.5
Vickers Hardness: 251 MPa
Brinell Hardness: 206 MPa
Speed of Sound: (r.t.) 2680 m·s-1
Pauling Electronegativity: 1.93
Sanderson Electronegativity: 1.83
Allred Rochow Electronegativity: 1.42
Mulliken-Jaffe Electronegativity: 1.47 (s orbital)
Allen Electronegativity: N/A
Pauling Electropositivity: 2.07
Reflectivity (%): 97
Refractive Index: N/A
Electrons: 47
Protons: 47
Neutrons: 61
Electron Configuration: [Kr]4d10 5s1
Atomic Radius: 145 pm
Atomic Radius,
non-bonded (Å):
Covalent Radius: 145±5 pm
Covalent Radius (Å): 1.36
Van der Waals Radius: 172 pm
Oxidation States: 1, 2, 3 (amphoteric oxide)
Phase: Solid
Crystal Structure: Cubic face centered
Magnetic Ordering: diamagnetic
Electron Affinity (kJ·mol-1) 125.58
1st Ionization Energy: 731.01 kJ·mol-1
2nd Ionization Energy: 2073.48 kJ·mol-1
3rd Ionization Energy: 2073.48 kJ·mol-1
CAS Number: 7440-22-4
EC Number: 231-131-3
MDL Number: MFCD00003397
Beilstein Number: N/A
SMILES Identifier: [Ag]
InChI Identifier: InChI=1S/Ag
PubChem CID: 23954
ChemSpider ID: 22394
Earth - Total: 44 ppb
Mercury - Total: 7.2 ppb
Venus - Total: 49 ppb
Earth - Seawater (Oceans), ppb by weight: 0.1
Earth - Seawater (Oceans), ppb by atoms: 0.0057
Earth -  Crust (Crustal Rocks), ppb by weight: 80
Earth -  Crust (Crustal Rocks), ppb by atoms: 20
Sun - Total, ppb by weight: 1
Sun - Total, ppb by atoms: 0.01
Stream, ppb by weight: 0.3
Stream, ppb by atoms: 0.003
Meterorite (Carbonaceous), ppb by weight: 140
Meterorite (Carbonaceous), ppb by atoms: 20
Typical Human Body, ppb by weight: N/A
Typical Human Body, ppb by atom: N/A
Universe, ppb by weight: 0.6
Universe, ppb by atom: 0.007
Discovered By: N/A
Discovery Date: before 5000 BC
First Isolation: N/A

Health, Safety & Transportation Information for Silver

Silver is not toxic although most silver salts are poisonous. Safety data for Silver and its compounds can vary widely depending on the form. For potential hazard information, toxicity, and road, sea and air transportation limitations, such as DOT Hazard Class, DOT Number, EU Number, NFPA Health rating and RTECS Class, please see the specific material or compound referenced in the Products tab. The below information applies to elemental (metallic) Silver.

Safety Data
Material Safety Data Sheet MSDS
Signal Word N/A
Hazard Statements N/A
Hazard Codes N/A
Risk Codes N/A
Safety Precautions N/A
RTECS Number N/A
Transport Information N/A
WGK Germany 3
Globally Harmonized System of
Classification and Labelling (GHS)

Silver Isotopes

Naturally occurring silver (Ag) has two stable isotopes: 107Ag and 109Ag.

Nuclide Isotopic Mass Half-Life Mode of Decay Nuclear Spin Magnetic Moment Binding Energy (MeV) Natural Abundance
(% by atom)
93Ag 92.94978(64)# 5# ms [>1.5 µs] Unknown 9/2+# N/A 746.1 -
94Ag 93.94278(54)# 37(18) ms [26(+26-9) ms] ß+ to 94Pd 0+# N/A 760.7 -
95Ag 94.93548(43)# 1.74(13) s ß+ to 95Pd; ß+ + p to 94Pd (9/2+) N/A 775.3 -
96Ag 95.93068(43)# 4.45(4) s ß+ to 96Pd; ß+ + p to 95Pd (8+) N/A 788.03 -
97Ag 96.92397(35) 25.3(3) s ß+ to 97Pd (9/2+) N/A 802.63 -
98Ag 97.92157(7) 47.5(3) s ß+ to 98Pd; ß+ + p to 97Pd (5+) N/A 812.58 -
99Ag 98.91760(16) 124(3) s ß+ to 99Pd (9/2)+ N/A 824.38 -
100Ag 99.91610(8) 2.01(9) min ß+ to 100Pd (5)+ N/A 833.39 -
101Ag 100.91280(11) 11.1(3) min ß+ to 101Pd 9/2+ N/A 847.06 -
102Ag 101.91169(3) 12.9(3) min ß+ to 102Pd 5+ N/A 855.14 -
103Ag 102.908973(18) 65.7(7) min EC to 103Pd 7/2+ 4.47 872.53 -
104Ag 103.908629(6) 69.2(10) min EC to 104Pd 5+ 3.92 880.61 -
105Ag 104.906529(12) 41.29(7) d EC to 105Pd 1/2- 0.1014 888.69 -
106Ag 105.906669(5) 23.96(4) min EC to 106Pd; ß- to 106Cd 1+ 3.71 896.77 51.839
107Ag 106.905097(5) STABLE - 1/2- -0.11357 904.85 -
108Ag 107.905956(5) 2.37(1) min EC to 108Pd; ß- to 108Cd 1+ 2.6884 912.93 48.161
109Ag 108.904752(3) STABLE - 1/2- -0.1306905 921.01 -
110Ag 109.906107(3) 24.6(2) s EC to 110Pd; ß- to 110Cd 1+ 2.7271 929.08 -
111Ag 110.905291(3) 7.45(1) d ß- to 111Cd 1/2- N/A 937.16 -
112Ag 111.907005(18) 3.130(9) h ß- to 112Cd 2(-) 0.0547 945.24 -
113Ag 112.906567(18) 5.37(5) h ß- to 113Cd 1/2- 0.159 953.32 -
114Ag 113.908804(27) 4.6(1) s ß- to 114Cd 1+ N/A 961.4 -
115Ag 114.90876(4) 20.0(5) min ß- to 115Cd 1/2- N/A 969.48 -
116Ag 115.91136(5) 2.68(10) min ß- to 116Cd (2)- N/A 968.24 -
117Ag 116.91168(5) 73.6(14) s [72.8(+20-7) s] ß- to 117Cd 1/2-# N/A 976.32 -
118Ag 117.91458(7) 3.76(15) s ß- to 118Cd 1- N/A 984.4 -
119Ag 118.91567(10) 6.0(5) s ß- to 119Cd 1/2-# N/A 992.48 -
120Ag 119.91879(8) 1.23(4) s ß- to 120Cd; ß- + n to 119Cd 3(+#) N/A 1000.55 -
121Ag 120.91985(16) 0.79(2) s ß- to 121Cd; ß- + n to 120Cd (7/2+)# N/A 1008.63 -
122Ag 121.92353(22)# 0.529(13) s ß- to 122Cd; ß- + n to 121Cd (3+) N/A 1007.4 -
123Ag 122.92490(22)# 0.300(5) s ß- to 123Cd; ß- + n to 122Cd (7/2+) N/A 1015.47 -
124Ag 123.92864(21)# 172(5) ms ß- to 124Cd; ß- + n to 123Cd 3+# N/A 1023.55 -
125Ag 124.93043(32)# 166(7) ms ß- to 125Cd; ß- + n to 124Cd (7/2+)# N/A 1022.32 -
126Ag 125.93450(32)# 107(12) ms ß- to 126Cd; ß- + n to 125Cd 3+# N/A 1030.39 -
127Ag 126.93677(32)# 79(3) ms ß- to 127Cd; ß- + n to 126Cd 7/2+# N/A 1038.47 -
128Ag 127.94117(32)# 58(5) ms Unknown N/A N/A 1037.24 -
129Ag 128.94369(43)# 44(7) ms [46(+5-9) ms] Unknown 7/2+# N/A 1045.31 -
130Ag 129.95045(36)# ~50 ms Unknown 0+ N/A 1044.08 -