General | States | Energies | Oxidation & Electrons |Appearance & Characteristics
Reactions | Other Forms |Radius | Conductivity | Abundance
Encyclopedia Britannica articles


Name Iodine Symbol I
atomic number 53 Atomic weight 126.9045
Density @ 293 K 4.93 g/cm3 Atomic volume 25.74 cm3/mol
Group Halogen discovered 1811


state (s, l, g) s
melting point 386.7 K boiling point 458.4 K
Heat of fusion 7.824 kJ/mol Heat of vaporization 20.752 kJ/mol
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1st ionization energy 1008.4 kJ/mole electronegativity 2.66
2nd ionization energy 1845.8 kJ/mole electron affinity 295.16 kJ/mole
3rd ionization energy 3184 kJ/mole Specific heat 0.214 J/gK
heat atomization 107 kJ/mole atoms

Oxidation & Electrons

Shells 2,8,18,18,7 electron configuration [Kr] 4d10 5s2 5p5
minimum oxidation number -1 maximum oxidation number 7
min. common oxidation no. 0 max. common oxidation no. 7
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Appearance & Characteristics

structure layers of I2 color bluish-black
uses nutrient, antiseptic toxicity yes
hardness mohs characteristics diatomic


reaction with air none reaction with 6M HCl none
reaction with 6M HCl none reaction with 15M HNO3 mild, = HIO3
reaction with 6M NaOH mild, = OI-, I-
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Other Forms

number of isotopes 1 hydride(s) HI
oxide(s) I2O5 I4O9 I2O4 chloride(s) ICl ICl3


ionic radius (2- ion) pm ionic radius (1- ion) 206 pm
atomic radius 133 pm ionic radius (1+ ion) pm
ionic radius (2+ ion) pm ionic radius (3+ ion) pm
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thermal conductivity 0.45 J/m-sec-deg electrical conductivity 0 1/mohm-cm
polarizability 5 A^3


source Brines, Chilean nitrate (misc) rel. abund. solar system -0.046 log
abundance earth's crust -0.3 log cost, pure 8.3 $/100g
cost, bulk $/100g
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World Wide Web presentation of Chemicool Periodic Table is © Copyright 1996-99 by David D. Hsu. Some data were provided by and used with the permission of JCE Software and is owned and copyright by the Division of Chemical Education, Inc. Additional data were provided by Perkin-Elmer through Peter Lykos of IIT. The information may not be redistributed without the permission of David Hsu or JCE Software.