knowledge unlocks a world of possibilities The Robinson Library

The Robinson Library About the Library Navigation Help Sitemap Terms of Use Contact Information

  ScienceChemistryChemical Elements
Technetium (Tc)

(tek nE' she em) the first synthesized element got its name from the Greek word for "artificial"

radioactive image obtained using a technetium isotope


atomic number 43
atomic mass 98.0 amu

melting point 3,915.0º F (2,157.0º C)
boiling point 7,709.0º F (4,265º C)

isotopes 26

Technetium is a silvery-gray metal that tarnishes slowly in moist air.


Elemental technectium does not naturally occur on Earth, but its spectral lines have been observed in S-, M-, and N-type stars.

The isotope technetium-99 is produced from the waste products of uranium nuclear fuel.


Tc-99 is used for radiactive tracing in medicine, and for equipment calibration.

Small amounts of technetium can retard the corrosion of steel, although this protection can only be applied to closed systems due to technetium's radioactivity.


Element 43 was predicted by Dmitri Mendeleev, creator of the periodic table, who called the "missing element" eka-manganese. It was first reported as having been discovered in Berlin, Germany, by Ida Tacke, Walter Noddack, and Otto Berg in 1925, at which time it was named masurium after the region in Prussia where Noddack was born. That discovery was disputed, however. It was conclusively isolated in 1937 by Carlo Perrier and Emilio Segrè at the University of Palermo in Sicily, who created elemental technetium by bombaring molybdenum atoms with deutrons that had been accelerated by a cyclotron. In 1962, technetium-99 was isolated and identified in African pitchblende (a uranium rich ore) in extremely minute quantities as a spontaneous fission product of uranium-238 by B.T. Kenna and P.K. Kuroda

Los Alamos National Laboratory

Emilio Segrè

Questions or comments about this page?

  The Robinson Library > Science > Chemistry > Chemical Elements

This page was last updated on 05/12/2016.

About This Site | Navigation Help | Sitemap | Terms of Use | Contact