Difference between revisions of "Technetium"
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Technetium has low chemical sensitivity, but ingestion or inhalation is very dangerous since it leads to continuous internal irradiation. | Technetium has low chemical sensitivity, but ingestion or inhalation is very dangerous since it leads to continuous internal irradiation. | ||
===Storage=== | ===Storage=== | ||
| − | The Tc<sup>99</sup> isotope can be stored in closed glass bottles. All the other more active isotopes should be stored in containers with thick lead walls. | + | The Tc<sup>99</sup> 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. |
===Disposal=== | ===Disposal=== | ||
Revision as of 19:56, 12 August 2020
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| General properties | |||||
|---|---|---|---|---|---|
| Name, symbol | Technetium, Tc | ||||
| Appearance | Silvery metallic | ||||
| Technetium in the periodic table | |||||
| |||||
| Atomic number | 43 | ||||
| Standard atomic weight (Ar) | 98.907 | ||||
| Group, block | 7; d-block | ||||
| Period | period 5 | ||||
| Electron configuration | [Kr] 4d5 5s2 | ||||
per shell | 2, 8, 18, 13, 2 | ||||
| Physical properties | |||||
| Phase | Solid | ||||
| 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) | ||||
| pressure | |||||
| Atomic properties | |||||
| Oxidation states | −3, −1, 0, +1, +2, +3, +4, +5, +6, +7 | ||||
| Electronegativity | Pauling scale: 1.9 (Pauling scale) | ||||
| energies |
1st: 702 kJ/mol 2nd: 1470 kJ/mol 3rd: 2850 kJ/mol | ||||
| Atomic radius | empirical: 136 pm | ||||
| Covalent radius | 147±7 pm | ||||
| Miscellanea | |||||
| 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) | ||||
| Magnetic ordering | Paramagnetic | ||||
| CAS Registry Number | 7440-26-8 | ||||
| History | |||||
| Prediction | Dmitri Mendeleev ((1871)) | ||||
| Discovery and first isolation | Emilio Segrè and Carlo Perrier (1937) | ||||
Technetium is a radioactive, grey metal. It is the lightest element that has no stable isotopes.
Contents
Properties
Chemical
The chemical properties of technetium lie in between those of Manganese and Rhenium. It has 9 oxidation states, the most common oxidation states of technetium are +4, +5, and +7.
Physical
Availability
Technetium is very rare and expensive. One can obtain it from certain element collector supplies. The price range is usually 400-1000€.
Isolation
Projects
- Element collection
Handling
Safety
Technetium has low chemical sensitivity, but ingestion or inhalation is very dangerous since it leads to continuous internal irradiation.
Storage
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.
