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Iodine |
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Pronunciation | (EYE-ə-dyne, -din, -deen) |
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Appearance | lustrous metallic gray, violet as a gas |
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Standard atomic weight Ar, std(I) | 7002126904470000000♠126.90447(3)[1] |
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Iodine in the periodic cairt |
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Atomic nummer (Z) | 53 |
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Group | group 17 (halogens) |
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Period | period 5 |
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Block | p-block |
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Element category | Reactive nonmetal |
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Electron confeeguration | [Kr] 4d10 5s2 5p5 |
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Electrons per shell | 2, 8, 18, 18, 7 |
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Pheesical properties |
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Phase at STP | solit |
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Meltin pynt | 386.85 K (113.7 °C, 236.66 °F) |
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Bylin pynt | 457.4 K (184.3 °C, 363.7 °F) |
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Density (near r.t.) | 4.933 g/cm3 |
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Treeple pynt | 386.65 K, 12.1 kPa |
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Creetical pynt | 819 K, 11.7 MPa |
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Heat o fusion | (I2) 15.52 kJ/mol |
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Heat o vapourisation | (I2) 41.57 kJ/mol |
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Molar heat capacity | (I2) 54.44 J/(mol·K) |
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Vapour pressur (rhombic)
P (Pa) |
1 |
10 |
100 |
1 k |
10 k |
100 k |
at T (K) |
260 |
282 |
309 |
342 |
381 |
457 |
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Atomic properties |
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Oxidation states | −1, +1, +3, +4, +5, +6, +7 strangly acidic |
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Electronegativity | Pauling scale: 2.66 |
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Atomic radius | empirical: 140 pm |
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Covalent radius | 139±3 pm |
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Van der Waals radius | 198 pm |
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Spectral lines o iodine |
Ither properties |
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Naitural occurrence | primordial |
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Creestal structur | orthorhombic |
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Thermal conductivity | 0.449 W/(m·K) |
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Electrical resistivity | 1.3×107 Ω·m (at 0 °C) |
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Magnetic orderin | diamagnetic[2] |
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Bulk modulus | 7.7 GPa |
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CAS Nummer | 7553-56-2 |
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History |
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Diskivery | Bernard Courtois (1811) |
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First isolation | Bernard Courtois (1811) |
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Main isotopes o iodine |
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Isotope |
Abundance |
Hauf-life (t1/2) |
Decay mode |
Product |
123I |
syn |
13 h |
ε, γ |
123Te |
124I |
syn |
4.176 d |
ε |
124Te |
125I |
syn |
59.40 d |
ε |
125Te |
127I |
100% |
- |
(SF) |
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129I |
trace |
1.57×107 y |
β− |
129Xe |
131I |
syn |
8.02070 d |
β−, γ |
131Xe |
135I |
syn |
6.57 h |
β− |
135Xe |
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Decay modes in parentheses are predictit, but hae nae yet been observed |
| references |