Cadmium is a chemical element wi the seembol Cd an atomic nummer 48. This saft, bluish-white metal is chemically seemilar tae the twa ither stable metals in group 12, zinc an mercur. Lik zinc, it prefers oxidation state +2 in maist o its compoonds an lik mercur it shaws a law meltin pynt compared tae transeetion metals. Cadmium an its congeners are nae always considered transeetion metals, in that thay dae nae hae pairtly filled d or f electron shells in the elemental or common oxidation states. The average concentration o cadmium in the Yird's crust is atween 0.1 an 0.5 pairts per million (ppm). It wis discovered in 1817 simultaneously bi Stromeyer an Hermann, baith in Germany, as an impurity in zinc carbonate.

Cadmium, 48Cd
Template:Infobox element/symbol-to-top-image/alt
Cadmium
Pronunciation/ˈkædmiəm/ (KAD-mee-əm)
Appearancesillery bluish-gray metallic
Standard atomic weight Ar, std(Cd)112.414(4)[1]
Cadmium in the periodic cairt
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 Airn Cobalt Nickel Capper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Siller (element) 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 Gowd Mercur (element) Thallium Leid (element) 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 Ununtrium Flerovium Ununpentium Livermorium Ununseptium Ununoctium
Zn

Cd

Hg
sillercadmiumindium
Atomic nummer (Z)48
Groupgroup 12
Periodperiod 5
Blockd-block
Element category  Post-transeetion metal
Electron confeeguration[Kr] 4d10 5s2
Electrons per shell2, 8, 18, 18, 2
Pheesical properties
Phase at STPsolit
Meltin pynt594.22 K ​(321.07 °C, ​609.93 °F)
Bylin pynt1040 K ​(767 °C, ​1413 °F)
Density (near r.t.)8.65 g/cm3
when liquid (at m.p.)7.996 g/cm3
Heat o fusion6.21 kJ/mol
Heat o vapourisation99.87 kJ/mol
Molar heat capacity26.020 J/(mol·K)
Vapour pressur
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 530 583 654 745 867 1040
Atomic properties
Oxidation states−2, +1, +2 (a mildly basic oxide)
ElectronegativityPauling scale: 1.69
Atomic radiusempirical: 151 pm
Covalent radius144±9 pm
Van der Waals radius158 pm
Colour lines in a spectral range
Colour lines in a spectral range
Spectral lines o cadmium
Ither properties
Naitural occurrenceprimordial
Creestal structurhexagonal close-packed (hcp)
Hexagonal close packed creestal structur for cadmium
Speed o soond thin rod2310 m/s (at 20 °C)
Thermal expansion30.8 µm/(m·K) (at 25 °C)
Thermal conductivity96.6 W/(m·K)
Electrical resistivity(22 °C) 72.7 n Ω·m
Magnetic orderindiamagnetic[2]
Young's modulus50 GPa
Shear modulus19 GPa
Bulk modulus42 GPa
Poisson ratio0.30
Mohs haurdness2.0
Brinell haurdness203 MPa
CAS Nummer7440-43-9
History
DiskiveryKarl Samuel Leberecht Hermann an Friedrich Stromeyer (1817)
First isolationKarl Samuel Leberecht Hermann an Friedrich Stromeyer (1817)
Named byFriedrich Stromeyer (1817)
Main isotopes o cadmium
Iso­tope Abun­dance Hauf-life (t1/2) Decay mode Pro­duct
106Cd 1.25% >4.1×1020 y (β+β+) 106Pd
107Cd syn 6.5 h ε 107Ag
108Cd 0.89% >4.1×1017 y (β+β+) 108Pd
109Cd syn 462.6 d ε 109Ag
110Cd 12.49% - (SF)
111Cd 12.8% - (SF)
112Cd 24.13% - (SF)
113Cd 12.22% 7.7×1015 y β 113In
113mCd syn 14.1 y β 113In
IT 113Cd
114Cd 28.73% >6.4×1018 y (ββ) 114Sn
115Cd syn 53.46 h β 115In
116Cd 7.49% 3.1×1019 y ββ 116Sn
Decay modes in parentheses are predictit, but hae nae yet been observed
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References

eedit
  1. Meija, Juris; et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure and Applied Chemistry. 88 (3): 265–91. doi:10.1515/pac-2015-0305.
  2. Lide, D. R., ed. (2000). "Magnetic susceptibility of the elements and inorganic compounds". [[CRC Handbook of Chemistry and Physics]] (PDF) (81st ed.). CRC Press. ISBN 978-0-8493-0481-1. URL–wikilink conflict (help)