< Template:Infobox caesiumRevision as of 11:15, 1 November 2020 by imported>Gonnym
[[Category:Template:Pagetype with short description]]
Caesium, 55Cs |
Caesium |
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Pronunciation | (Template:Respell) |
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Alternative name | cesium (US, informal) |
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Appearance | pale gold |
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Standard atomic weight Ar, std(Cs) | Template:Val[1] |
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Caesium in the periodic table |
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Atomic number (Z) | 55 |
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Group | group 1: H and alkali metals |
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Period | period 6 |
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Block | s-block |
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Electron configuration | [Xe] 6s1 |
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Electrons per shell | 2, 8, 18, 18, 8, 1 |
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Physical properties |
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Phase at STP | solid |
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Melting point | 301.7 K (28.5 °C, 83.3 °F) |
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Boiling point | 944 K (671 °C, 1240 °F) |
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Density (near r.t.) | 1.93 g/cm3 |
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when liquid (at m.p.) | 1.843 g/cm3 |
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Critical point | 1938 K, 9.4 MPa[2] |
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Heat of fusion | 2.09 kJ/mol |
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Heat of vaporization | 63.9 kJ/mol |
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Molar heat capacity | 32.210 J/(mol·K) |
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Vapor pressure
P (Pa)
|
1
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10
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100
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1 k
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10 k
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100 k
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at T (K)
|
418
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469
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534
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623
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750
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940
|
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Atomic properties |
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Oxidation states | −1, +1[3] (a strongly basic oxide) |
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Electronegativity | Pauling scale: 0.79 |
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Ionization energies | - 1st: 375.7 kJ/mol
- 2nd: 2234.3 kJ/mol
- 3rd: 3400 kJ/mol
-
|
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Atomic radius | empirical: 265 pm |
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Covalent radius | 244±11 pm |
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Van der Waals radius | 343 pm |
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Spectral lines of caesium |
Other properties |
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Natural occurrence | primordial |
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Crystal structure | body-centered cubic (bcc) |
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Thermal expansion | 97 µm/(m·K) (at 25 °C) |
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Thermal conductivity | 35.9 W/(m·K) |
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Electrical resistivity | 205 nΩ·m (at 20 °C) |
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Magnetic ordering | paramagnetic[4] |
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Young's modulus | 1.7 GPa |
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Bulk modulus | 1.6 GPa |
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Mohs hardness | 0.2 |
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Brinell hardness | 0.14 MPa |
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CAS Number | 7440-46-2 |
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History |
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Naming | from Latin caesius, sky blue, for its spectral colours |
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Discovery | Robert Bunsen and Gustav Kirchhoff (1860) |
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First isolation | Carl Setterberg (1882) |
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Main isotopes of caesium |
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Category: Caesium | references |
References
These references will appear in the article, but this list appears only on this page.
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