Silver

Silver, ₄₇Ag
Silver
Appearance	lustrous white metal
Standard atomic weight Ar°(Ag)
	107.8682(2)
Silver in the periodic table
	palladium ← silver → cadmium
Atomic number (Z)	47
Group	group 11
Period	period 5
Block	d-block
Electron configuration	[Kr] 4d10 5s1
Electrons per shell	2, 8, 18, 18, 1
Physical properties
Phase at STP	solid
Melting point	1234.93 K (961.78 °C, 1763.2 °F)
Boiling point	2435 K (2162 °C, 3924 °F)
Density (near r.t.)	10.49 g/cm3
when liquid (at m.p.)	9.320 g/cm3
Heat of fusion	11.28 kJ/mol
Heat of vaporization	254 kJ/mol
Molar heat capacity	25.350 J/(mol·K)
Atomic properties
Oxidation states	−2, −1, 0, +1, +2, +3 (an amphoteric oxide)
Electronegativity	Pauling scale: 1.93
Ionization energies	1st: 731.0 kJ/mol ; 2nd: 2070 kJ/mol ; 3rd: 3361 kJ/mol ; ;
Atomic radius	empirical: 144 pm
Covalent radius	145±5 pm
Van der Waals radius	172 pm
	Spectral lines of silver
Other properties
Natural occurrence	primordial
Crystal structure	face-centered cubic (fcc)
Speed of sound thin rod	2680 m/s (at r.t.)
Thermal expansion	18.9 µm/(m⋅K) (at 25 °C)
Thermal conductivity	429 W/(m⋅K)
Thermal diffusivity	174 mm2/s (at 300 K)
Electrical resistivity	15.87 nΩ⋅m (at 20 °C)
Magnetic ordering	diamagnetic
Molar magnetic susceptibility	−19.5×10−6 cm3/mol (296 K)
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	206–250 MPa
CAS Number	7440-22-4
History
Discovery	before 5000 BC
Symbol	"Ag": from Latin argentum
Isotopes of silver v; e;
γ	–
γ	–
IT	108Ag
γ	–
γ	–
γ	–
	Category: Silver; view; talk; edit; \| references

Silver (symbol Ag) is a chemical element. In chemistry, silver is element 47, a transition metal. It has an atomic weight of 107.86 a.m.u. Its symbol is Ag, from the Latin word for silver, argentum.

Properties

Physical properties

Silver is a soft metal. It is also a precious metal. When it is used in money or in jewellery, it is often alloyed with gold or some other metal to make it harder. It is bluish-white. Among metals, it is the most reflective and the best conductor of electricity and heat. It is also very malleable and ductile, which means it can be pulled into wire or hammered into thin sheets.

Chemical properties

Silver is less reactive than most other metals, because of its full 4d shell. Its electron configuration is similar to copper and gold.^[6] It does not dissolve in most acids, but nitric acid dissolves it to make silver nitrate. It does react with strong oxidizing agents like potassium dichromate or potassium permanganate. It does not corrode easily. It only corrodes when there is hydrogen sulfide in the air. Then, it forms a black coating known as tarnish.

Silver exists in three main oxidation states: +1, +2 and +3. The +1 is much more common than +2 and +3. A few compounds exist in the +2 and +3 oxidation states, but they are very strong oxidizing agents. Silver compounds can be brown, black, yellow, gray, or colorless. Silver compounds are disinfectants.

Silver(I) compounds

Silver(I) compounds are oxidizing agents. They are more common. Most of them are very expensive.

Silver bromide, light yellow
Silver carbonate, yellowish
Silver chloride, white
Silver(I) fluoride, yellow-brown
Silver iodate, colorless
Silver iodide, yellow
Silver nitrate, colorless
Silver oxide, brown-black
Silver sulfide, black

Silver(II) compounds

Silver(II) compounds are powerful oxidizing agents and rare.

Silver(II) fluoride, strong oxidizing agent, highly reactive, white or gray

Silver(III) compounds

Silver(III) compounds are even rarer, and highly reactive

potassium tetrafluoroargentate

Silver sources

Silver can be found as a native metal. Most silver is found with copper, lead, or gold in rocks. The rocks are found mostly in Canada, Mexico, Peru, and the United States. Peru produces the most silver, mostly in mines that are operated for copper and zinc.

Silver is also in chemical compounds. Acanthite is a silver ore that is a silver compound.

Silver is extracted from its ores in several ways. It is normally extracted as a byproduct of electrolysis producing copper.

Uses

As an element

Silver has been used for many thousands of years by people all over the world, for jewellery, as money, and many other things. It is called a white metal even though it looks grey. The word silver is also used to talk about this color or shade of grey. Silver is also used for utensils. Silver is used as a catalyst.

In alloys

Silver can be alloyed with gold, copper, zinc, cadmium, tin, nickel, lead, bismuth, germanium, and mercury. The most common silver alloy is called sterling silver, which is 92.5% silver and 7.5% copper. Sometimes a small amount of germanium is added to prevent tarnish. An alloy of silver and mercury (an amalgam) is used to fill teeth in dentistry. Silver is added to some solder alloys in small amounts (5% or less), where it acts to make the solder more durable, more conductive, and less vulnerable to tin pest. The common lead-free SAC305 solder used in electronics contains 3% silver. Leaded solder can also contain silver, but this is less common.

In compounds

Silver compounds are disinfectants. It can kill bacteria and have other useful properties. It is used in the silver oxide battery. They are also used in photographic film. They can also be used to reduce odors in clothes. Some silver compounds are used in creams that help burns heal.

History

Silver has been used for thousands of years. It was normally considered second to gold in value. Many people including Romans and Chinese used silver as money. The symbol Ag is from the Latin name for silver, argentum. Silver was also used to prevent infections and decay.

Safety

Silver is not a large danger to humans. Silver compounds are toxic. They make the skin turn blue. Some can be carcinogens. Colloidal silver, a common homeopathic remedy, is not toxic in normal amounts, but it does not do much. Silver is very toxic to fish, so silver-containing waste (for example, photographic chemicals or silver oxide batteries) must not be released into the environment and should be properly recycled. Silver should not be stored near ammonia, acetylene, or strong acids, as these can react with silver to make unstable silver salts.

References

↑ "Standard Atomic Weights: Silver". CIAAW. 1985.
↑ Ag(0) has been observed in carbonyl complexes in low-temperature matrices: see McIntosh, D.; Ozin, G. A. (1976). "Synthesis using metal vapors. Silver carbonyls. Matrix infrared, ultraviolet-visible, and electron spin resonance spectra, structures, and bonding of silver tricarbonyl, silver dicarbonyl, silver monocarbonyl, and disilver hexacarbonyl". J. Am. Chem. Soc. 98 (11): 3167–75. doi:10.1021/ja00427a018.
↑ Lide, D. R., ed. (2005). "Magnetic susceptibility of the elements and inorganic compounds". CRC Handbook of Chemistry and Physics (PDF) (86th ed.). Boca Raton (FL): CRC Press. ISBN 0-8493-0486-5.
↑ Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.
↑ Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
↑ Hammond, C. R. (2004). The Elements, in Handbook of Chemistry and Physics. CRC press. ISBN 9780849304859.

Other websites

Silver -Citizendium

[1] "Standard Atomic Weights: Silver". CIAAW. 1985.

[2] Ag(0) has been observed in carbonyl complexes in low-temperature matrices: see McIntosh, D.; Ozin, G. A. (1976). "Synthesis using metal vapors. Silver carbonyls. Matrix infrared, ultraviolet-visible, and electron spin resonance spectra, structures, and bonding of silver tricarbonyl, silver dicarbonyl, silver monocarbonyl, and disilver hexacarbonyl". J. Am. Chem. Soc. 98 (11): 3167–75. doi:10.1021/ja00427a018.

[3] Lide, D. R., ed. (2005). "Magnetic susceptibility of the elements and inorganic compounds". CRC Handbook of Chemistry and Physics (PDF) (86th ed.). Boca Raton (FL): CRC Press. ISBN 0-8493-0486-5.

[4] Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.

[NUBASE2020-5] Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.

[6] Hammond, C. R. (2004). The Elements, in Handbook of Chemistry and Physics. CRC press. ISBN 9780849304859.

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