Technetium Facts

What is technetium? Technetium is a chemical element, having the atomic number 43 and symbol Tc, found in minute quantities in the earth's crust and now primarily produced synthetically. Its discovery is credited to the scientists Carlo Perrier and Emilio Segre in the year 1937, although the search went on for many years. It was the missing element, responsible for the gap in the periodic table between molybdenum (element number 42) and ruthenium (element number 44). Technetium is now produced artificially and has industrial and chemical applications. It is also used in nuclear medicine and biology.

All About Technetium

Physical Characteristics
Technetium is a silvery-gray colored stable metal which tarnishes on exposure to moisture in the air. It remains solid at room temperature. Its melting point is 2157 °C, while its boiling point is 4265 °C. In physical appearance it resembles platinum and is radioactive in nature.

Chemical Characteristics
Since it is located in the seventh group of the periodic table between rhenium and manganese, its chemical properties fall in between these two chemical elements, though it resembles rhenium more than it does to manganese. Technetium will dissolve in aqua regia (nitro-hydrochloric acid), nitric acid and concentrated sulfuric acid. It does not dissolve in hydrochloric acid.

Isotopes
One of the many interesting technetium facts is that it is the element with the lowest atomic number in the periodic table to have unstable isotopes (all isotopes of technetium are radioactive). The only other element to display this behavior is promethium (atomic number 61). Typically, odd-numbered elements have fewer stable isotopes compared to their even-numbered counterparts. The most stable isotopes of technetium are technetium-98, technetium-97 and technetium-99.

Production
Since this element is rare naturally, it is produced as a byproduct in the operations of nuclear reactors. Specifically, technetium-99 is produced by the nuclear fission of uranium-235 as well as plutonium-235. As a result, it is present in radioactive waste and is also produced on the detonation of nuclear weapons. More than two-thirds of the global supply of technetium is handled by the Chalk River reactor in Ontario, Canada and the Petten reactor in the Netherlands.

Disposal
Three of the isotopes of technetium have significantly long half-lives, each exceeding 2 million years with technetium-99 exhibiting a half-life of 211,000 years. The half-life of an element is the time taken for the element to reduce in half by decay. As a result, the disposal of this element is a valid and very real environmental concern. It is found in the waste material mainly near defense-related facilities, academic institutions and research facilities as well as facilities with nuclear reactors. Current regulations prevent the release of around more than 90 TBq, which is approximately 140 kg per year. Research facilities are involved in the exploration of techniques for the suitable disposal of technetium which will reduce environmental issues.

Uses
Technetium is used in nuclear medicine to carry out a number of medical tests, mainly relating to imaging and functional studies of internal bodily organs like bone scan. It is also used industrially for equipment calibration following its approval as a standard beta emitter. In the chemical industry, it functions as an effective catalyst, but its radioactive nature poses a practical problem. Owing to its radioactivity, precautions such as wearing a fume hood must be taken when handling technetium.

The discovery of technetium and its subsequent application have helped in the advancement of medical tests and tools. I hope this article helped you to understand the nature of this elusive element.