Technetiumis a chemical element with the symbol Tc and atomic number 43. The word technetium derived from the Greek word technetos which means artificial. Nearly all Tc is produced as a synthetic element, and only about 18,000 tons are estimated to exist at any given time in the Earth’s crust. Naturally occurring technetium is a spontaneous fission product in uranium ore and thorium ore, the most common source, or the product of neutron capture in molybdenum ores. This silvery gray, crystalline transition metal lies between manganese and rhenium in group 7 of the periodic table.
Characteristics of Technetium
- It is a silvery-gray transition metal. It tarnishes slowly in moist air. It dissolves in nitric acid, aqua regia (nitro-hydrochloric acid) and concentrated sulfuric acid, but is not soluble in any strength of hydrochloric acid.
- The metal form is slightly paramagnetic, meaning its magnetic dipoles align with external magnetic fields, but will assume random orientations once the field is removed.
- Pure, metallic, single-crystal Tc becomes a type-II superconductor at temperatures below 7.46 K. Below this temperature, technetium has a very high magnetic penetration depth, greater than any other element except niobium.
- Metallic technetium slowly tarnishes in moist air and, in powder form, burns in oxygen.
- It is located in the seventh group of the periodic table, between rhenium and manganese.
- It more closely resembles rhenium, particularly in its chemical inertness and tendency to form covalent bonds. Unlike manganese,
- It does not readily form cations (ions with a net positive charge). Tc exhibits nine oxidation states from −1 to +7, with +4, +5, and +7 being the most common. Technetium dissolves in aqua regia, nitric acid, and concentrated sulfuric acid, but it is not soluble in hydrochloric acid of any concentration.