Periodic Table -> Technetium
Technetium DetailsTechnetium Symbol:
TcTechnetium Atomic Number:
43Technetium Atomic Weight:
(98)What is Technetium?
(symbol Tc, atomic number 43) is a transition element with a silvery gray color. It was first detected by the Japanese scientist Masataka Ogawa in 1908. Emilio Segre and Carlo Perrier discovered the element in 1936. The name comes from technetos in Greek, meaning "artificial". Today, technetium is isolated in laboratories only. Deuterium nuclei are used to bombard molybdenum and isolate Tc. It is also formed through reactions of hydrogen and pertechnatate and hydrogen and sulphide.
Isotopes, Compounds, and Properties
This metal has a hexagonal close-packed structure and is paramagnetic. Common oxidation states include +7, +5, and +4. The element reacts with sulfuric acid, nitric acid, and aqua regia. It is radioactive, silvery grey in color, and has no stable isotopes. There are 9 isotopes, including Tc-100, Tc-99m, Tc-99, Tc-98, Tc-95, and others. Tc-100, for example, has a half life of about 14 minutes while Tc-95 has a half life of 20 hours. This is a d-block element with relatively high boiling and melting points of 4877 oC and 2157 oC, respectively. It forms carbides, tellurides, selenides, sulfides, oxides, and other compounds.
Occurrence and Production
This element is artificially produced but small amounts are found in the Earth’s crust, mainly in uranium ores. However, significant amounts have been produced in nuclear reactors. Te-99m is found in different sites, including hospitals, laboratories, universities, fuel cycle facilities, and nuclear reactors. In the universe, the metal is found in N-, M-, and S-type stars.
Applications and Therapies
One of the isotopes, Tc-99m is used to treat circulatory system diseases. It is used in combination with a tin compound in post-heart attack treatments. Te-99m is mainly used for research and medical purposes, for example, to assess the condition of internal organs such as the spleen, liver, lungs, kidneys, and heart. Patients with a history of diabetes, kidney and liver disease,
and children may receive alternative treatments and therapies or may be administered lower doses to avoid excessive radiation exposure. It is usually administered as an injection in the vein.
Te-99m is among the most commonly used radioisotopes. Tc-99 can be used in nuclear batteries as well. The element is also catalyst similar to elements such as palladium and rhenium. While there are many possible uses, one problem is that technetium is radioactive.
Health Hazards, Environmental Pollution and Radioactivity
Tc-99 is considered a health hazard and must be handled with care. It is released in the environment through airborne emissions, nuclear weapons, facilities used to store radioactive materials, and the processing of nuclear fuel. Higher concentrations are reported near weapons facilities. The isotope is found in rock sediments, animal and plant species, soils, air, and water. Te-99 is found in high concentrations in some aquatic species such as brown algae.
Technetium also contributes to environmental pollution because considerable quantities are produced through the fission of uranium and uranium-235 in particular. It forms solid, liquid, and airborne waste with a long half life of about 220,000 years. In contrast, the half life of Tc-99m is only 6 hours. Radiation exposure increases the risk for leukemia and bone cancer, and young patients are at a higher risk than older ones. At the same time, Tc-99m is safer to use compared to other radioactive isotopes. Side effects such as dizziness, confusion, discomfort, chest pain, and blurred vision require medical attention. Radiation exposure is also associated with side effects such as joint inflammation, vomiting, nausea, gait abnormality, and other skeletal, heart, and gastrointestinal problems. Te-99 enters the body through contaminated water and food and is accumulated in the gastrointestinal tract and the thyroid gland.
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