technetium

American  

[tek-nee-shee-uhm, -shuhm] / tɛkˈni ʃi əm, -ʃəm /

noun

1. Chemistry. an element of the manganese family, not found in nature, but obtained in the fission of uranium or by the bombardment of molybdenum. Tc; 99; 43; 11.5.

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technetium British  

/ tɛkˈniːʃɪəm /

noun

1. a silvery-grey metallic element, artificially produced by bombardment of molybdenum by deuterons: used to inhibit corrosion in steel. The radioisotope technetium-99m , with a half-life of six hours, is used in radiotherapy. Symbol: Tc; atomic no: 43; half-life of most stable isotope, ⁹⁷ Tc: 2.6 × 10 ⁶ years; valency: 0, 2, 4, 5, 6, or 7; relative density: 11.50 (calculated); melting pt: 2204°C; boiling pt: 4265°C

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technetium Scientific  

/ tĕk-nē′shē-əm /

1. A silvery-gray, radioactive metallic element. It was the first element to be artificially made, and it is produced naturally in extremely small amounts during the radioactive decay of uranium. Technetium is used to remove corrosion from steel. Its longest-lived isotope is Tc 98 with a half-life of 4,200,000 years. Atomic number 43; melting point 2,200°C; specific gravity 11.50; valence 0, 2, 4, 5, 6, 7.

2. See Periodic Table

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Etymology

Origin of technetium

1945–50; < Greek technēt ( ós ) artificial (literally, made, verbid of technâsthai; techno- ) + -ium

Example Sentences

Like all elements first born in cyclotrons, technetium was radioactive.

From The New Yorker • Dec. 27, 2019

That means it’s likely that the operator had been recently exposed to the technetium when a different patient was cremated.

From The Verge • Feb. 26, 2019

A number of artificial elements, including technetium, astatine, and the transuranium elements, have been produced in this way.

From Textbooks • Feb. 14, 2019

After it is injected, the location of the technetium compound, and hence the damaged tissue, can be determined by detecting the γ rays emitted by the Tc-99 isotope.

From Textbooks • Feb. 14, 2019

Wait too long, and the technetium will decay away altogether - it has a half-life of six hours - or be flushed out of Sarah's body.

From BBC • May 29, 2015