CAS Number7440-39-3
PubChem CID5355457
Atomic Radius222
Atomic Volume39,24
Atomic Weight137,327
Boiling Point1.897
Bulk Modulus
CategoryAlkaline earth metals
Crystal StructureBody Centered Cubic
Covalent Radius215
Electrical Resistivity
Electron Configuration[Xe] 6s2
Electrons per shell2, 8, 18, 18, 8, 2
Heat of Fusion8
Heat of Vaporization140
Ionization Potential5,212
Magnetic Ordering
Magnetic Susceptibility
Mass Number56
Melting Point727
Atomic Number137
Oxidation States2
Poisson Ratio
Shear Modulus
Specific Heat Capacity0,204
Thermal Conductivity0,184
Van der Waals radius
Young's Modulus
Abundance in Earth's crust0.034%
Abundance in Universe1×10-6%
Ba Бариум 56 137.327 2 6 s 56 725.0 1640.0 [Xe] 6s2 2 8 18 18 8 2 3.5 0.034% Silver Cubic: Body centered 0.9 0.881 {"1":"502.9","2":"965.2","3":"3600"} 508 13.95 198 2 2.22 39.0 8.01 140.2 0.204 18.4 0 Solid, Paramagnetic, Conductor, AlkalineEarthMetal, Metal, Stable, Natural BAR-i-em Soft, slightly malleable, silvery-white metal. Barite, or barium sulfate (BaSO4), when ground is used as a filter for rubber, plastics, and resins. It is insoluable in water and so is used in X-rays of the digestive system. Barium nitrate, Ba(NO3)2, burns brilliant green and is used in fireworks. Found in barytine (BaSO4) and witherite (BaCO3), never found in pure form due to its reactivity. Must be stored under kerosene to remain pure. IQ2u1JunzgA Barium
Element 43 was predicted on the basis of the periodic table, and was erroneously reported as having been discovered in 1925, at which time it was named masurium.

The element was actually discovered by Carlo Perrier and Emilio Segrè in 1937.

It was also found in a sample of molybdenum sent by Ernest Lawrence that was bombarded by deuterons in the Berkeley cyclotron. From the Greek word technetos, artificial 56 1808 Sir Humphrey Davy England From the Greek word "barys" meaning "heavy"

Isotopes of Technetium

Standard Atomic Weight


Stable Isotopes

130Ba 132Ba 134Ba 135Ba 136Ba 137Ba 138Ba

Unstable Isotopes

114Ba 115Ba 116Ba 117Ba 118Ba 119Ba 120Ba 121Ba 122Ba 123Ba 124Ba 125Ba 126Ba 127Ba 128Ba 129Ba 131Ba 133Ba 139Ba 140Ba 141Ba 142Ba 143Ba 144Ba 145Ba 146Ba 147Ba 148Ba 149Ba 150Ba 151Ba 152Ba 153Ba

Technetium is harmful due to its radioactivity
Technetium was the first element to be produced artificially
Technetium is used in nuclear medicine to carry out a number of medical tests, mainly relating to imaging and functional studies of internal bodily organs like bone scan.

It is also used industrially for equipment calibration following its approval as a standard beta emitter.

Mild carbon steels may be effectively protected by minute quantities of technetium, but this corrosion protection is limited to closed systems because of technetium's radioactivity.