Nepedia
Back to Discover
Advanced Reader
⚛️

Technetium

physical science Maturity 11-13 Next article →

Technetium is a unique chemical element with the symbol Tc and atomic number 43. It is a silvery-gray, crystalline transition metal. This metal is quite unusual because it is the lightest element whose isotopes are all radioactive. In the periodic table, it is located in group 7. This placement puts it between manganese and rhenium. Because of this position, its chemical properties are intermediate between those two neighbors.

Periodisches System der Elemente (1904-1945, now Gdansk University of Technology)
Periodisches System der Elemente (1904-1945, now Gdansk University of Technology)

Technetium is primarily a synthetic element. This means most of it is produced by humans in a laboratory rather than being found in large amounts in nature. One way it is made is through the fission of uranium-235 in nuclear reactors. Scientists extract long-lived isotopes from the resulting nuclear fuel rods. However, small amounts do occur naturally. It can be found in uranium or thorium ores as a spontaneous fission product. It can also form in molybdenum ores through a process called neutron capture.

The history of discovering technetium is filled with many attempts and errors. In the 1860s, Dmitri Mendeleev noticed a gap in his periodic table. He predicted a missing element existed between molybdenum and ruthenium. He gave this predicted element the provisional name eka-manganese. Many researchers claimed to find the element before it was officially discovered. They often misidentified other materials like iridium or niobium. In 1925, Walter Noddack, Otto Berg, and Ida Tacke reported finding element 43. They called it masurium, but other scientists could not replicate their results.

The official discovery finally happened in 1937. Carlo Perrier and Emilio Segrè confirmed the element at the University of Palermo in Sicily. They used a molybdenum foil that had been made radioactive in a cyclotron. This machine is a type of particle accelerator. By using comparative chemistry, they proved the activity came from element 43. Because it was the first element produced artificially, it was named technetium. This name comes from the Greek word for artificial.

First technetium-99m generator - 1958
First technetium-99m generator - 1958

Technetium has very important uses in modern medicine. One specific version is called technetium-99m. This is a short-lived nuclear isomer that emits gamma rays. Doctors use it in nuclear medicine for many different diagnostic tests. For example, it is used to help diagnose bone cancer. This isotope is used in about ten million medical procedures every year. It is a vital tool for seeing how the body is working.

Basedow-vor-nach-RIT
Basedow-vor-nach-RIT

This element also helped scientists understand the life of stars. In 1952, astronomer Paul W. Merrill detected technetium in the light of red giants. Red giants are stars that are near the end of their lives. Because technetium is short-lived, its presence in these stars was a major discovery. It proved that stars can produce heavier elements through nuclear reactions. This process is known as nucleosynthesis. This finding helped confirm that stars act as factories for the elements in our universe.

Technetium also shows interesting physical and chemical behaviors. As a metal, it is slightly paramagnetic. This means its magnetic dipoles align when a magnetic field is applied. Pure single-crystal technetium can also become a type-II superconductor. This happens when it is cooled below a very low temperature. Chemically, it can form many different types of compounds. One common form is sodium pertechnetate, which is used in various applications.

Pertechnetate1
Pertechnetate1

It can also form halides, which are compounds made of technetium and a halogen. These structures can range from simple molecules to complex three-dimensional networks.

Chloro-containing coordination complexes of technetium (Tc-99)
Chloro-containing coordination complexes of technetium (Tc-99)
570 words

Where will your curiosity go next?

Keep exploring at your chosen reading level.

🖼️ Images & Media (7)
File:Periodisches System der Elemente (1904-1945, now Gdansk University of Technology).jpg
Periodisches System der Elemente...
File:Pertechnetate1.svg
Pertechnetate1.svg
File:Zirconium-tetrachloride-3D-balls-A.png
Zirconium-tetrachloride-3D-balls-A.png
File:Chloro-containing coordination complexes of technetium (Tc-99).jpg
Chloro-containing coordination complexes...
File:Tc CNCH2CMe2(OMe) 6Cation.png
Tc CNCH2CMe2(OMe) 6Cation.png
File:First technetium-99m generator - 1958.jpg
First technetium-99m generator - 1958.jpg
File:Basedow-vor-nach-RIT.jpg
Basedow-vor-nach-RIT.jpg
More to explore

🔬 Go deeper

More advanced topics to explore

🪜 Step back

Simpler topics to build understanding

What is Nepedia?

A free, ad-free encyclopedia for children. Every article is written at five reading levels, so the same page works for a five-year-old and a fifteen-year-old — use the level switcher above to see this one change. No account needed to read.