Zinc

Zinc,  ₃₀Zn

General properties
Appearance	silver-gray
Standard atomic weight (Ar, standard)	7001653800000000000♠65.38(2)
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 copper ← zinc → gallium
Atomic number (Z)	30
Group	group 12
Period	period 4
Element category	post-transition metal, alternatively considered a transition metal
Block	d-block
Electron configuration	[Ar] 3d10 4s2
Electrons per shell	2, 8, 18, 2
Physical properties
Phase at STP	solid
Melting point	692.68 K ​(419.53 °C, ​787.15 °F)
Boiling point	1180 K ​(907 °C, ​1665 °F)
Density (near r.t.)	7.14 g/cm3
when liquid (at m.p.)	6.57 g/cm3
Heat of fusion	7.32 kJ/mol
Heat of vaporization	115 kJ/mol
Molar heat capacity	25.470 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)
Electronegativity	Pauling scale: 1.65
Ionization energies	1st: 906.4 kJ/mol 2nd: 1733.3 kJ/mol 3rd: 3833 kJ/mol (more)
Atomic radius	empirical: 134 pm
Covalent radius	122±4 pm
Van der Waals radius	139 pm
Spectral lines
Miscellanea
Crystal structure	​hexagonal close-packed (hcp)
Speed of sound thin rod	3850 m/s (at r.t.) (rolled)
Thermal expansion	30.2 µm/(m·K) (at 25 °C)
Thermal conductivity	116 W/(m·K)
Electrical resistivity	59.0 nΩ·m (at 20 °C)
Magnetic ordering	diamagnetic
Magnetic susceptibility	−11.4·10−6 cm3/mol (298 K)
Young's modulus	108 GPa
Shear modulus	43 GPa
Bulk modulus	70 GPa
Poisson ratio	0.25
Mohs hardness	2.5
Brinell hardness	327–412 MPa
CAS Number	7440-66-6
History
Discovery	Indian metallurgists (before 1000 BCE)
First isolation	Andreas Sigismund Marggraf (1746)
Recognized as a unique metal by	Rasaratna Samuccaya (800)
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
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Zinc is a chemical element with symbol Zn and atomic number 30. It is the first element in group 12 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. 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, Iraq, the United Arab Emirates, Kalmykia, Turkmenistan and Georgia, and the second millennium BC in West India, Uzbekistan, Iran, Syria, Iraq, and Israel (Judea). 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. The mines of Rajasthan have given definite evidence of zinc production going back to the 6th century BC. 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.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 zinc methyl or zinc diethyl in the organic laboratory.

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