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Cadmium (Cd)

Cadmium is a chemical element of the periodic table with chemical symbol Cd and atomic number 48 with an atomic weight of 112.414 u and is classed as transition metal and is part of group 12 (zinc group). Cadmium is solid at room temperature.

Cadmium in the periodic table

Atomic number48
Group12 (Zinc group)
ClassificationTransition Metal
AppearanceSilvery bluish-gray metallic
Color Silver
Number of protons48 p+
Number of neutrons64 n0
Number of electrons48 e-
From Wikipedia, the free encyclopediaCadmium is a chemical element with symbol Cd and atomic number 48. This soft, bluish-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. Like zinc, it prefers oxidation state +2 in most of its compounds and like mercury it shows a low melting point compared to transition metals.

Physical properties

Phase at STPSolid
Density8.65 g/cm3
Atomic weight112.414 u

Thermal properties

Melting point594.22 K
321.07 °C
609.926 °F
Boiling point1040 K
766.85 °C
1412.33 °F
Heat of vaporization99.87 kJ/mol

Atomic properties

Electronegativity (Pauling Scale)1.69
Electron affinity-68 kJ/mol
Oxidation states−2, +1, +2
(a mildly basic oxide)
Ionization energies
  1. 867.8 kJ/mol
  2. 1631.4 kJ/mol
  3. 3616 kJ/mol

Electron configuration for cadmium

Electron configuration
Shorthand configuration
[Kr] 4d10 5s2
Electron configuration
Full configuration
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2
Electron configuration chart
Electrons per shell2, 8, 18, 18, 2
Valence electrons 2
Valency electrons 2
Bohr model
CadmiumElectron shell for Cadmium, created by Injosoft ABCd
Figure: Shell diagram of Cadmium (Cd) atom.
Orbital Diagram

The history of Cadmium

Discovery and first isolationKarl Samuel Leberecht Hermann, Friedrich Stromeyer, Karl Samuel Leberecht Hermann (1817)
Named byFriedrich Stromeyer (1817)
Discovery of cadmium
Cadmium (Latin cadmia, Greek καδμεία meaning "calamine", a cadmium-bearing mixture of minerals that was named after the Greek mythological character Κάδμος, Cadmus, the founder of Thebes) was discovered in contaminated zinc compounds sold in pharmacies in Germany in 1817 by Friedrich Stromeyer. Karl Samuel Leberecht Hermann simultaneously investigated the discoloration in zinc oxide and found an impurity, first suspected to be arsenic, because of the yellow precipitate with hydrogen sulfide. Additionally Stromeyer discovered that one supplier sold zinc carbonate instead of zinc oxide. Stromeyer found the new element as an impurity in zinc carbonate (calamine), and, for 100 years, Germany remained the only important producer of the metal. The metal was named after the Latin word for calamine, because it was found in this zinc ore. Stromeyer noted that some impure samples of calamine changed color when heated but pure calamine did not. He was persistent in studying these results and eventually isolated cadmium metal by roasting and reducing the sulfide.


List of unique identifiers for Cadmium in various chemical registry databases
CAS Number7440-43-9
ChemSpider ID22410
EC number231-152-8
PubChem CID Number23973