Technetium is a silvery-gray metal that tarnishes slowly in moist air. The common oxidation states of technetium are +7, +5, and +4. Under oxidizing conditions technetium (VII) will exist as the pertechnetate ion, TcO4-. The chemistry of technetium is said to be similar to that of rhenium.
Technetium-99m is used to image the skeleton and heart muscle in particular, but also for brain, thyroid, lungs, liver, spleen, kidney, gall bladder, bone marrow, salivary and lachrymal glands, heart blood pool, infection and numerous specialized medical studies.
Technetium is a fission product of uranium and does not occur naturally, and there are no non-radioactive isotopes of Tc. Technetium-99 (half-life = 2.1 × 105 years), is the most common isotope found in water. The oxidized form of technetium, the pertechnetate anion (TcO4−), is very soluble and mobile in groundwater.
Technetium holds a unique place in the periodic table as the first element to be synthesized artificially. In 1937, Italian physicists Emilio Segrè and Carlo Perrier discovered technetium by bombarding molybdenum with deuterons in a cyclotron. This marked a significant advancement in our understanding of elements and their creation.
Despite its artificial origins, trace amounts of technetium exist naturally on Earth. This is because it can be formed through the spontaneous fission of uranium, albeit in incredibly small quantities. However, these natural traces are dwarfed by the amount produced artificially for various applications.