Reed Relays and
Electronics India Limited
Manufacturer of Reed Switches, Reed Sensors and Reed-based products
Reed Relays and Electronics India Limited Incorporated in 1971


Cadmium is a chemical element with the symbol Cd and atomic number 48. This soft bluish-white metal is chemically similar to Zinc and Mercury, and is toxic. This metal is banned by the RoHS directive of 2011.

Cadmium (Wikipedia)

Cadmium is a chemical element; it has symbol Cd and atomic number 48. This soft, silvery-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. Like zinc, it demonstrates oxidation state +2 in most of its compounds, and like mercury, it has a lower melting point than the transition metals in groups 3 through 11. Cadmium and its congeners in group 12 are often not considered transition metals, in that they do not have partly filled d or f electron shells in the elemental or common oxidation states. The average concentration of cadmium in Earth's crust is between 0.1 and 0.5 parts per million (ppm). It was discovered in 1817 simultaneously by Stromeyer and Hermann, both in Germany, as an impurity in zinc carbonate.

Cadmium, 48Cd
Pronunciation/ˈkædmiəm/ (KAD-mee-əm)
Appearancesilvery bluish-gray metallic
Standard atomic weight Ar°(Cd)
Cadmium 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


Atomic number (Z)48
Groupgroup 12
Periodperiod 5
Block  d-block
Electron configuration[Kr] 4d10 5s2
Electrons per shell2, 8, 18, 18, 2
Physical properties
Phase at STPsolid
Melting point594.22 K ​(321.07 °C, ​609.93 °F)
Boiling point1040 K ​(767 °C, ​1413 °F)
Density (at 20° C)8.649 g/cm3
when liquid (at m.p.)7.996 g/cm3
Heat of fusion6.21 kJ/mol
Heat of vaporization99.87 kJ/mol
Molar heat capacity26.020 J/(mol·K)
Vapor pressure
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
Ionization energies
  • 1st: 867.8 kJ/mol
  • 2nd: 1631.4 kJ/mol
  • 3rd: 3616 kJ/mol
Atomic radiusempirical: 151 pm
Covalent radius144±9 pm
Van der Waals radius158 pm
Color lines in a spectral range
Spectral lines of cadmium
Other properties
Natural occurrenceprimordial
Crystal structurehexagonal close-packed (hcp) (hP2)
Lattice constants
Hexagonal close packed crystal structure for cadmium
a = 297.89 pm
c = 561.66 pm (at 20 °C)
Thermal expansion30.95×10−6/K (at 20 °C)
Thermal conductivity96.6 W/(m⋅K)
Electrical resistivity72.7 nΩ⋅m (at 22 °C)
Magnetic orderingdiamagnetic
Molar magnetic susceptibility−19.8×10−6 cm3/mol
Young's modulus50 GPa
Shear modulus19 GPa
Bulk modulus42 GPa
Speed of sound thin rod2310 m/s (at 20 °C)
Poisson ratio0.30
Mohs hardness2.0
Brinell hardness203–220 MPa
CAS Number7440-43-9
Discovery and first isolationKarl Samuel Leberecht Hermann and Friedrich Stromeyer (1817)
Named byFriedrich Stromeyer (1817)
Isotopes of cadmium
Main isotopes Decay
abun­dance half-life (t1/2) mode pro­duct
106Cd 1.25% stable
107Cd synth 6.5 h ε 107Ag
108Cd 0.89% stable
109Cd synth 462.6 d ε 109Ag
110Cd 12.5% stable
111Cd 12.8% stable
112Cd 24.1% stable
113Cd 12.2% 8.04×1015 y β 113In
113mCd synth 14.1 y β 113In
IT 113Cd
114Cd 28.8% stable
115Cd synth 53.46 h β 115In
116Cd 7.51% 2.8×1019 y ββ 116Sn
 Category: Cadmium
| references

Cadmium occurs as a minor component in most zinc ores and is a byproduct of zinc production. Cadmium was used for a long time[when?] as a corrosion-resistant plating on steel, and cadmium compounds are used as red, orange, and yellow pigments, to color glass, and to stabilize plastic. Cadmium use is generally decreasing because it is toxic (it is specifically listed in the European Restriction of Hazardous Substances Directive) and nickel–cadmium batteries have been replaced with nickel–metal hydride and lithium-ion batteries. Due to it being a neutron poison, cadmium is also used as a component of control rods in nuclear fission reactors. One of its few new uses is in cadmium telluride solar panels.

Although cadmium has no known biological function in higher organisms, a cadmium-dependent carbonic anhydrase has been found in marine diatoms.

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