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|Name, symbol||Technetium, Tc|
|Technetium in the periodic table|
|Standard atomic weight (Ar)||98.907|
|Group, block||7; d-block|
|Electron configuration||[Kr] 4d5 5s2|
|2, 8, 18, 13, 2|
|Density near r.t.||11 g/cm3|
|Heat of fusion||33.29 kJ/mol|
|Heat of||585.2 kJ/mol|
|Molar heat capacity||24.27 J/(mol·K)|
|Oxidation states||−3, −1, 0, +1, +2, +3, +4, +5, +6, +7|
|Electronegativity||Pauling scale: 1.9 (Pauling scale)|
1st: 702 kJ/mol |
2nd: 1470 kJ/mol
3rd: 2850 kJ/mol
|Atomic radius||empirical: 136 pm|
|Covalent radius||147±7 pm|
|Speed of sound thin rod||16,200 m/s (at 20 °C)|
|Thermal expansion||7.1 µm/(m·K) (at 20°C)|
|Thermal conductivity||50.6 W/(m·K)|
|Electrical resistivity||200 Ω·m (at 20 °C)|
|CAS Registry Number||7440-26-8|
|Prediction||Dmitri Mendeleev ((1871))|
|Discovery and first isolation||Emilio Segrè and Carlo Perrier (1937)|
Technetium is a radioactive, grey metal with the atomic number 43. It is the lightest element that has no stable isotopes.
Technetium is a silvery radioactive metal.
Technetium is very rare and expensive. Bulk amounts of technetium are near impossible to obtain.
However, one can obtain it from certain element collector supplies as plated on metal foils. The price range is usually 400-1000€ for technetium plated foil.
- Element collection
Technetium has low chemical toxicity, but ingestion or inhalation is very dangerous since it leads to radiation poisoning.
The Tc99 isotope can be stored in closed glass bottles, or, preferably, ampoules. All the other more active isotopes should be stored in containers with thick lead walls.