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Iodine

Non-Metalsolid
Symbol: I
Atomic number: 53
Atomic mass: 126.90447
Group: Halogen
CAS-number: 7553-56-2

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Physical data
Isotopes
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Physical data

Electronic dataThermal dataSteric data
Shells: 2, 8, 18, 18, 7
Orbitals: [Kr] 4d10 5s2 5p5
Electronegativity: 2.5, 2.2
1. Ionization potential: 10.4513 eV
2. Ionization potential: 19.131 eV
3. Ionization potential: 33.0 eV
Oxidation states: 7, 5, 1, -1
Electrical conductivity: 8.0e-16 10^6
Melting point: 113.5 °C
Boiling point: 184.35 °C
Specific heat: 0.214 J/gK
Heat of fusion: 7.824 kJ/mol
Heat of vaporization: 20.752 kJ/mol
Thermal conductivity: 0.00449 W/cmK
Atomic radius: 1.32 Å
Ionic radius: 2.20 Å (-1)
Covalent radius: 1.33 Å
Atomic volume: 25.74 cm³/mol
Density (293 K): 4.93 g/cm³
Crystal structure: orthorhombic
orthorhombic

Isotopes

NuclideAbundance [%]MassSpinHalflifeDecay modeDecay tree
122I 0 122 1 3.62m β+, EC View
123I 0 123 5/2 13.2h EC View
124I 0 124 2 4.18d EC, β+ View
125I 0 125 5/2 60.1d EC View
126I 0 126 2 13.0d EC, β-, β+ View
127I 100 126.905 5/2 -- --
128I 0 128 1 25.00m β-, EC, β+ View
129I 0 129 7/2 1.57E07y β- View
130I 0 130 5 12.36h β- View
131I 0 131 7/2 8.04d β-, β- View
132I 0 132 4 2.28h β- View
133I 0 133 7/2 20.8h β-, β- View
134I 0 134 4 52.6m β- View
135I 0 135 7/2 6.57h β-, β- View
136I 0 136 2 1.39m β- View

Other info

Name origin:Greek: iôeides (violet colored).
Description:Shiny, black, non-metallic solid; as a gas it is violet and intensely irritating to the eyes, nose and throat.
Discovered by:Bernard Courtois
Year:1811
Place:France
Sources:Occurs on land and in the sea in sodium and potassium compounds.
Use(s):Required in small amounts by humans. Once used as an antiseptic, but no longer due to its poisonous nature.