Zinc

Zinc, 30Zn
Zinc fragment sublimed and 1cm3 cube.jpg
Zinc
Appearancesilver-gray
Standard atomic weight Ar°(Zn)
  • 65.38±0.02
  • 65.38±0.02 (abridged)[1]
Zinc in the periodic table
Hydrogen Helium
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson


Zn

Cd
copperzincgallium
Atomic number (Z)30
Groupgroup 12
Periodperiod 4
Block  d-block
Electron configuration[Ar] 3d10 4s2
Electrons per shell2, 8, 18, 2
Physical properties
Phase at STPsolid
Melting point692.68 K ​(419.53 °C, ​787.15 °F)
Boiling point1180 K ​(907 °C, ​1665 °F)
Density (near r.t.)7.14 g/cm3
when liquid (at m.p.)6.57 g/cm3
Heat of fusion7.32 kJ/mol
Heat of vaporization115 kJ/mol
Molar heat capacity25.470 J/(mol·K)
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 610 670 750 852 990 1179
Atomic properties
Oxidation states−2, 0, +1, +2 (an amphoteric oxide)
ElectronegativityPauling scale: 1.65
Ionization energies
  • 1st: 906.4 kJ/mol
  • 2nd: 1733.3 kJ/mol
  • 3rd: 3833 kJ/mol
  • (more)
Atomic radiusempirical: 134 pm
Covalent radius122±4 pm
Van der Waals radius139 pm
Color lines in a spectral range
Spectral lines of zinc
Other properties
Natural occurrenceprimordial
Crystal structurehexagonal close-packed (hcp)
Hexagonal close packed crystal structure for zinc
Speed of sound thin rod3850 m/s (at r.t.) (rolled)
Thermal expansion30.2 µm/(m⋅K) (at 25 °C)
Thermal conductivity116 W/(m⋅K)
Electrical resistivity59.0 nΩ⋅m (at 20 °C)
Magnetic orderingdiamagnetic
Molar magnetic susceptibility−11.4×10−6 cm3/mol (298 K)[2]
Young's modulus108 GPa
Shear modulus43 GPa
Bulk modulus70 GPa
Poisson ratio0.25
Mohs hardness2.5
Brinell hardness327–412 MPa
CAS Number7440-66-6
History
DiscoveryIndian metallurgists (before 1000 BCE)
First isolationAndreas Sigismund Marggraf (1746)
Recognized as a unique metal byRasaratna Samuccaya (1300)
Main isotopes of zinc
Iso­tope Abun­dance Half-life (t1/2) Decay mode Pro­duct
64Zn 49.2% stable
65Zn syn 244 d ε 65Cu
γ
66Zn 27.7% stable
67Zn 4.0% stable
68Zn 18.5% stable
69Zn syn 56 min β 69Ga
69mZn syn 13.8 h β 69Ga
70Zn 0.6% stable
71Zn syn 2.4 min β 71Ga
71mZn syn 4 d β 71Ga
72Zn syn 46.5 h β 72Ga
 Category: Zinc
| references

Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a silvery-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodic table. In some respects, zinc is chemically similar to magnesium: both elements exhibit only one normal oxidation state (+2), and the Zn2+ and Mg2+ ions are of similar size.[note 1] Zinc is the 24th most abundant element in Earth's crust and has five stable isotopes. The most common zinc ore is sphalerite (zinc blende), a zinc sulfide mineral. The largest workable lodes are in Australia, Asia, and the United States. Zinc is refined by froth flotation of the ore, roasting, and final extraction using electricity (electrowinning).

Brass, an alloy of copper and zinc in various proportions, was used as early as the third millennium BC in the Aegean area and the region which currently includes Iraq, the United Arab Emirates, Kalmykia, Turkmenistan and Georgia. In the second millennium BC it was used in the regions currently including West India, Uzbekistan, Iran, Syria, Iraq, and Israel.[3][4][5] Zinc metal was not produced on a large scale until the 12th century in India, though it was known to the ancient Romans and Greeks.[6] The mines of Rajasthan have given definite evidence of zinc production going back to the 6th century BC.[7] To date, the oldest evidence of pure zinc comes from Zawar, in Rajasthan, as early as the 9th century AD when a distillation process was employed to make pure zinc.[8] Alchemists burned zinc in air to form what they called "philosopher's wool" or "white snow".

The element was probably named by the alchemist Paracelsus after the German word Zinke (prong, tooth). German chemist Andreas Sigismund Marggraf is credited with discovering pure metallic zinc in 1746. Work by Luigi Galvani and Alessandro Volta uncovered the electrochemical properties of zinc by 1800. Corrosion-resistant zinc plating of iron (hot-dip galvanizing) is the major application for zinc. Other applications are in electrical batteries, small non-structural castings, and alloys such as brass. A variety of zinc compounds are commonly used, such as zinc carbonate and zinc gluconate (as dietary supplements), zinc chloride (in deodorants), zinc pyrithione (anti-dandruff shampoos), zinc sulfide (in luminescent paints), and dimethylzinc or diethylzinc in the organic laboratory.

Zinc is an essential mineral, necessary for prenatal and postnatal development.[9] Zinc deficiency affects about two billion people in the developing world and is associated with many diseases.[10] In children, deficiency causes growth retardation, delayed sexual maturation, infection susceptibility, and diarrhea.[9] Enzymes with a zinc atom in the reactive center are widespread in biochemistry, such as alcohol dehydrogenase in humans.[11] Consumption of excess zinc may cause ataxia, lethargy, and copper deficiency.

  1. ^ "Standard Atomic Weights: Zinc". CIAAW. 2007.
  2. ^ Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.
  3. ^ Thornton, C. P. (2007). Of brass and bronze in prehistoric Southwest Asia (PDF). Papers and Lectures Online. Archetype Publications. ISBN 978-1-904982-19-7. Archived (PDF) from the original on September 24, 2015.
  4. ^ Cite error: The named reference Greenwood1997p1201 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference jas5 was invoked but never defined (see the help page).
  6. ^ "Zinc - Royal Society Of Chemistry". Archived from the original on July 11, 2017.
  7. ^ "India Was the First to Smelt Zinc by Distillation Process". Infinityfoundation.com. Archived from the original on May 16, 2016. Retrieved April 25, 2014.
  8. ^ Kharakwal, J. S. & Gurjar, L. K. (December 1, 2006). "Zinc and Brass in Archaeological Perspective". Ancient Asia. 1: 139–159. doi:10.5334/aa.06112.
  9. ^ a b Hambidge, K. M. & Krebs, N. F. (2007). "Zinc deficiency: a special challenge". J. Nutr. 137 (4): 1101–5. doi:10.1093/jn/137.4.1101. PMID 17374687.
  10. ^ Cite error: The named reference Prasad2003 was invoked but never defined (see the help page).
  11. ^ Maret, Wolfgang (2013). "Chapter 14 Zinc and the Zinc Proteome". In Banci, Lucia (ed.). Metallomics and the Cell. Metal Ions in Life Sciences. Vol. 12. Springer. pp. 479–501. doi:10.1007/978-94-007-5561-1_14. ISBN 978-94-007-5561-1. PMID 23595681.


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