Technetium (Tc) Element: Important Properties, Uses, Health Effects

Technetium is a metallic element with the atomic number 43 and is represented by the symbol ‘Tc’ in the periodic table. It is classified as a transition metal and belongs to the d-block of group 7 of the periodic table. It is the lightest element with all allotropes being radioactive.

Technetium is a silvery-gray radioactive metal that looks similar to platinum and is commonly extracted as a gray powder.It is a rare element that is produced as a result of fusion.

History of Technetium

• Russian chemist Dmitri Mendeleev first predicted the existence of technetium in 1871. He identified a gap
• In 1925, a group of German chemists, Ida Tacke, Otto Berg, and Walter Noddack, in Berlin claimed that they had discovered element 43 after a number of tests were performed on platinum ores and columbite minerals. between manganese and ruthenium and termed it eka-manganese.
• Carlo Perrier, an Italian chemist, and Emilio Segre, an Italian American physicist discovered it in 1937. Technetium was generated by impacting molybdenum atoms with deuterons propelled by a cyclotron device.
• The term ‘technetium’ is derived from the Greek word ‘technètos,’ which means “artificial.”

Occurrence of Technetium

• Technetium is one of the rarest elements on Earth. Its presence on the Earth’s crust is estimated to be only 0.003 parts per trillion.
• Technetium is found naturally on Earth only in uranium ores because of spontaneous fission; the levels are minute but have been quantified.
• Technetium was previously assumed to exist only in laboratory samples. Its spectral lines, however, have now been observed in red giant stars such as Betelgeuse.
• The radioactive isotope technetium-99 can be created from uranium nuclear reactor waste.

Isotopes of Technetium

Technetium does not have naturally stable isotopes.

Elemental Properties of Technetium

Physical Properties of Technetium

• Technetium is a silvery-gray radioactive element.
• Technetium has a melting point of 2430 K (2157 °C) and a boiling point of around 4538 K (4265 °C).
• Its density is 11.5 grams per cubic centimeter.
• Technetium is good electric and thermal conductor.
• It can be an excellent superconductor at temperatures of -262.15 °C and below.
• It is slightly para magnetic.

Chemical Properties of Technetium

• In a powdered state, it ignites with oxygen, resulting in heptoxide (Tc₂O₇).
• Technetium dissolves in nitric acid and concentrated sulfuric acid but is not soluble in hydrochloric acid of any strength.

Chemical Reaction of Technetium

• The Reaction of Technetium with Air

It tarnishes very slowly in wet air. In reality, technetium is often distributed as a powder or a sponge, and it is significantly more reactive in this form. When heated with oxygen, technetium (VII) oxide (technetium heptoxide, Tc₂O₇) is formed.

4 Tc (s) + 7 O₂ (g) → 2 Tc₂O₇ (s)

• The Reaction of Technetium with Water

Technetium does not react with water under normal conditions.

• The Reaction of Technetium with the Halogens

When heated with fluorine, the result is a mixture of technetium (VI) fluoride (technetium hexafluoride, TcF₆) and technetium (VII) fluoride (technetium heptafluoride, TcF₇).

Tc (s) + 3 F₂ (g) → TcF₆ (s)

2 Tc (s) + 7 F₂ (g) → 2 TcF₇ (s)

• The Reaction of Technetium with Acids

 technetium is insoluble in hydrochloric acid (HCl) and hydrofluoric acid (HF). It does dissolve in nitric acid, HNO₃, or concentrated sulphuric acid, H₂SO₄, both of which are oxidizing, to form solutions of pertechnetic acid, HTcO₄. In this form, the technetium is in the formal +7 oxidation state.

Uses of Technetium

• Technetium helps to protect steel from corrosion as it is corrosion-resistant.
• Technetium-99m is among the most valuable isotopes of technetium because it has a short half-life and chemically interacts with many biologically active substances; these features make it excellent for many medical radioactive isotope tests.
• When Tc-99m is coupled with a tin compound, it clings to red blood cells and can therefore be used to map circulatory disorders.
• Tc-99m’s pyrophosphate ion binds to calcium deposits in injured heart muscle, making it effective for assessing damage after a heart attack.
• Tc-99m allows imaging of the organ’s anatomy, such as the spleen.

Health Effects Of Technetium

• Technetium has no natural biological function and is not found in the human body.
• The technetium isotopes must be handled with caution. When dealing with technetium, the greatest concern is dust inhalation; such radioactive contamination in the lungs can represent a high cancer risk.

Environmental Effects Of Technetium

Nuclear fission produces a large amount of technetium, which spreads more easily than many other radionuclides. It appears to be chemically non-toxic.

References

• W. M. Haynes, ed., CRC Handbook of Chemistry and Physics, CRC Press/Taylor and Francis, Boca Raton, FL, 95th Edition, Internet Version 2015, accessed December 2014.
• John Emsley, Nature’s Building Blocks: An A-Z Guide to the Elements, Oxford University Press, New York, 2nd Edition, 2011.
• Hammond, C. R. (2004). “The Elements”. Handbook of Chemistry and Physics  CRC press. ISBN 978-0-8493-0485-9.
• https://www.rsc.org/periodic-table/element/43/technetium
• https://www.britannica.com/science/technetium
• Cotton, F. A.; Wilkinson, G.; Murillo, C. A.; Bochmann, M. (1999). Advanced Inorganic Chemistry (6th ed.). New York: John Wiley & Sons, Inc. ISBN 978-0-471-19957-1.
• https://www.lenntech.com/periodic/elements/tc.htm
• https://www.sciencedirect.com/topics/physics-and-astronomy/technetium
• https://www.epa.gov/radiation/radionuclide-basics-technetium-99