53
126.90
I
Iodine
Identification
CAS Number: 7553-56-2
Discovery Year: 1811
Discoverer: Bernard Courtois
Discovery Location: France
Properties
Atomic Dimensions
Atomic Radius: 140 pm →
Atomic Radius (Rahm): 238 pm
Covalent Radius: 139 pm →Van der Waals Radius: 198 pm
Atomic Volume: 25.7 cm³/mol
Lattice Constant: 7.72 Å
Thermodynamics
Melting Point: 386.7 K →Boiling Point: 457.5 K →Heat of Fusion: 15.52 kJ/mol →Heat of Vaporization: 41.95 kJ/mol →
Heat of Formation: 106.757 kJ/mol
Electronic Structure
Electron Config: [Kr] 4d10 5s2 5p5
Block: p
Period: 5 →Group: 17 →Electronegativity: 2.66 →Electron Affinity: 3.0590368 eV →Oxidation States: -1, +1, +5, +7
Abundance & Geochemistry
Crust Abundance: 0.45 mg/kg
Sea Abundance: 0.06 mg/L
Geochemical Class: semi-volatile
Goldschmidt Class: litophile
About
Dark violet nonmetallic element, belongs to group 17 of the periodic table. Insoluble in water. Required as a trace element for living organisms. One stable isotope, I-127 exists, in addition to fourteen radioactive isotopes. Chemically the least reactive of the halogens, and the most electropositive metallic halogen. Discovered in 1812 by Courtois.
Isotopes
I-127 127 100.00%