Basic Information

Name: Iodine 
Symbol: I 
Atomic Number: 53 
Atomic Mass: 126.90447 amu 
Melting Point: 113.5 °C (386.65 K, 236.3 °F) 
Boiling Point: 184.0 °C (457.15 K, 363.2 °F) 
Number of Protons/Electrons: 53 
Number of Neutrons: 74 
Classification: Halogen 
Crystal Structure: Orthorhombic 
Density @ 293 K: 4.93 g/cm3 
Color: blackish
Date of Discovery: 1811 
Discoverer: Bernard Courtois 
Name Origin: From the Greek word iôdes (violet) 
Uses: required in humans 
Obtained From: sodium and potassium compounds