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Oxidation & Electrons | Appearance & Characteristics Reactions | Compounds | Radius | Conductivity Abundance & Isotopes 
Technetium is radioactive. |
General:
| Name: Technetium | Symbol: Tc |
| Type: Transition Metal | Atomic weight: 98.9062 |
| Density @ 293 K: 11.5 g/cm3 | Atomic volume: 8.5 cm3/mol |
| Discovered: Technetium was discovered by Carlo Perrier and Emilio Segrè in Italy in 1937. They found the technetium isotope 97Tc in a sample of molybdenum which had previously been bombarded with deuterium nuclei. Technetium was the first element to be produced synthetically. The element is named after the Greek word 'technètos', meaning artificial. | |
States
| State (s, l, g): solid | |
| Melting point: 2433 K (2160 oC) | Boiling point: 4533 K (4260 oC) |
Energies
| Specific heat capacity: 0.21 J g-1 K-1 | Heat of atomization: 661 kJ mol-1 |
| Heat of fusion: 24.0 kJ mol-1 | Heat of vaporization : 502 kJ mol-1 |
| 1st ionization energy: 702.4 kJ mol-1 | 2nd ionization energy: 1472.4 kJ mol-1 |
| 3rd ionization energy: 2850.2 kJ mol-1 | Electron affinity: 53 kJ mol-1 |
Oxidation & Electrons
| Shells: 2,8,18,14,1 | Electron configuration: [Kr] 4d6 5s1 |
| Minimum oxidation number: -3 | Maximum oxidation number: 7 |
| Min. common oxidation no.: 0 | Max. common oxidation no.: 7 |
| Electronegativity (Pauling Scale): 1.9 | Polarizability volume: 11.4 Å3 |
Appearance & Characteristics
| Structure: hcp: hexagonal close packed | Color: silvery gray |
| Harmful effects: Technetium is harmful due to its radioactivity. | Hardness: mohs |
| Characteristics: Technetium is an exceptionally rare, silvery-gray metal that tarnishes slowly in moist air. In powder form, it burns in oxygen to the heptoxide (Tc2O7). Technetium dissolves in nitric acid and concentrated sulfuric acid, but is not soluble in hydrochloric acid of any strength. Is an excellent superconductor at temperatures of 11 K and below. Technetium and promethium are notable among the light elements because they both have no stable isotopes. | |
| Uses: 99mTc, with a half-life of six hours, is used in radiotherapy. 95Tc, with a half-life of 61 days, is used as a radioactive tracer. 99Tc, has a very long half-life (2.11 X 105 years) and decays almost entirely by beta decay with no gamma rays. It is used as for equipment calibration. In small concentrations the pertechnetate ion (TcO 4-) can protect carbon steels and iron from corrosion. This use is limited to closed systems due to its radioactivity. | |
Reactions
| Reaction with air: mild, w/ht, ⇒ Tc2O7 | Reaction with 6 M HCl: none |
| Reaction with 15 M HNO3: mild, ⇒ HTcO4 (Pertechnetic acid) | Reaction with 6 M NaOH: |
Compounds
| Oxide(s): TcO2, Tc2O7 | Chloride(s): TcCl4, TcCl6 |
| Hydride(s): none |
Radius
| Atomic radius: 136 pm | Ionic radius (1+ ion): pm |
| Ionic radius (2+ ion): pm | Ionic radius (3+ ion): pm |
| Ionic radius (2- ion): pm | Ionic radius (1- ion): pm |
Conductivity
| Thermal conductivity: 50.6 W m-1 K-1 | Electrical conductivity: 0.1 x 10-6 S cm-1 |
Abundance & Isotopes
| Abundance earth's crust: parts per million by weight, parts per million by moles | |
| Abundance solar system: parts per billion by weight, part per billion by moles | |
| Cost, pure: $ per 100g | |
| Cost, bulk: $ per 100g | |
| Source: Technetium has found naturally found in minute quantities in uranium ore. The isotope 99Tc is produced from the waste products of uranium nuclear fuel. 99mTc is produced from irradiated 98Mo (technetium cow). The spectral signature of technetium has been detected in light from S-type red giant stars. | |
| Isotopes: Technetium has 26 isotopes whose half-lives are known, with mass numbers from 88 to 113. None are stable. The most stable and most common isotope is 99Tc, with a half-life of 2.11 X 105 years. | |
