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Tc - Technetium

Technetium

 Technetium 
Tc
Atomic Number: 43
Atomic Weight: -98.0
Element Type: Transition Metal
Crystal Structure: Hexagonal
Melting Point: 2157.0°C = 3914.6°F = 2430.15 K
Boiling Point: 4265.0°C = 7709.0°F = 4538.15 K
Critical Temp: °C = °F = K
Atomic Radius: 1.95 Å (Å = Angstrom = 10-10 m)
Covalent Radius: 1.27 Å
Electronegativity: 2.1

History

(Gr. technetos, artificial) Element 43 was predicted on the basis of the periodictable, and was erroneously reported as having been discovered in 1925, at which time itwas named masurium. The element was actually discovered by Perrier and Segre in Italy in1937. It was found in a sample of molybdenum, which was bombarded by deuterons in theBerkeley cyclotron, and which E. Lawrence sent to these investigators. Technetium was thefirst element to be produced artificially. Since its discovery, searches for the elementin terrestrial material have been made.  Finally in 1962, technetium-99 was isolatedand identified in African pitchblende (a uranium rich ore) in extremely minute quantitiesas a spontaneous fission product of uranium-238 by B.T. Kenna and P.K. Kuroda.  If itdoes exist, the concentration must be very small. Technetium has been found in thespectrum of S-, M-, and N-type stars, and its presence in stellar matter is leading to newtheories of the production of heavy elements in the stars.


Sources


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(1629-1695)


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