Revision as of 22:15, 21 February 2021 by imported>Auric
[[Category:Template:Pagetype with short description]]
Technetium, 43Tc| Technetium |
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| Pronunciation | (Template:Respell) |
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| Appearance | shiny gray metal |
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| Mass number | [97] |
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| Technetium in the periodic table |
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|
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| Atomic number (Z) | 43 |
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| Group | group 7 |
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| Period | period 5 |
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| Block | d-block |
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| Electron configuration | [Kr] 4d5 5s2 |
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| Electrons per shell | 2, 8, 18, 13, 2 |
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| Physical properties |
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| Phase at STP | solid |
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| Melting point | 2430 K (2157 °C, 3915 °F) |
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| Boiling point | 4538 K (4265 °C, 7709 °F) |
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| Density (near r.t.) | 11 g/cm3 |
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| Heat of fusion | 33.29 kJ/mol |
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| Heat of vaporization | 585.2 kJ/mol |
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| Molar heat capacity | 24.27 J/(mol·K) |
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Vapor pressure (extrapolated)
| P (Pa)
|
1
|
10
|
100
|
1 k
|
10 k
|
100 k
|
| at T (K)
|
2727
|
2998
|
3324
|
3726
|
4234
|
4894
|
|
| Atomic properties |
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| Oxidation states | −3, −1, 0, +1,[1] +2, +3,[1] +4, +5, +6, +7 (a strongly acidic oxide) |
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| Electronegativity | Pauling scale: 1.9 |
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| Ionization energies | - 1st: 702 kJ/mol
- 2nd: 1470 kJ/mol
- 3rd: 2850 kJ/mol
-
|
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| Atomic radius | empirical: 136 pm |
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| Covalent radius | 147±7 pm |
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| Spectral lines of technetium |
| Other properties |
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| Natural occurrence | from decay |
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| Crystal structure | hexagonal close-packed (hcp) |
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| Speed of sound thin rod | 16,200 m/s (at 20 °C) |
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| Thermal expansion | 7.1 µm/(m·K)[2] (at r.t.) |
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| Thermal conductivity | 50.6 W/(m·K) |
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| Electrical resistivity | 200 nΩ·m (at 20 °C) |
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| Magnetic ordering | Paramagnetic |
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| Magnetic susceptibility | +270.0·10−6 cm3/mol (298 K)[3] |
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| CAS Number | 7440-26-8 |
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| History |
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| Prediction | Dmitri Mendeleev (1871) |
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| Discovery and first isolation | Emilio Segrè and Carlo Perrier (1937) |
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| Main isotopes of technetium |
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|
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Category: Technetium | references |
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References
These references will appear in the article, but this list appears only on this page.
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