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Pronunciation | (pə-LOH-nee-əm) |
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Allotropes | α, β |
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Appearance | silvery |
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Mass number | [209] |
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Group | group 16 (chalcogens) |
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Period | period 6 |
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Block | p-block |
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Electron configuration | [Xe] 4f14 5d10 6s2 6p4 |
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Electrons per shell | 2, 8, 18, 32, 18, 6 |
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Phase at STP | solid |
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Melting point | 527 K (254 °C, 489 °F) |
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Boiling point | 1235 K (962 °C, 1764 °F) |
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Density (near r.t.) | alpha: 9.196 g/cm3 beta: 9.398 g/cm3 |
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Heat of fusion | ca. 13 kJ/mol |
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Heat of vaporization | 102.91 kJ/mol |
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Molar heat capacity | 26.4 J/(mol·K) |
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Vapor pressure
P (Pa) |
1 |
10 |
100 |
1 k |
10 k |
100 k |
at T (K) |
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(846) |
1003 |
1236 |
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Oxidation states | −2, +2, +4, +5,[1] +6 (an amphoteric oxide) |
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Electronegativity | Pauling scale: 2.0 |
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Ionization energies | |
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Atomic radius | empirical: 168 pm |
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Covalent radius | 140±4 pm |
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Van der Waals radius | 197 pm |
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Spectral lines of polonium |
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Natural occurrence | from decay |
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Crystal structure | cubic |
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Thermal expansion | 23.5 µm/(m⋅K) (at 25 °C) |
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Thermal conductivity | 20 W/(m⋅K) (?) |
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Electrical resistivity | α: 0.40 µΩ⋅m (at 0 °C) |
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Magnetic ordering | nonmagnetic |
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CAS Number | 7440-08-6 |
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Discovery | 1898 |
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First isolation | Willy Marckwald (1902) |
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Category: Polonium | references |