Thanks to Meridith for this beautiful photograph taken during laboratory. This shows the chameleon-like behavior of iodine – one color in a polar solvent (dark orange) and a different color in a non-polar (hexane) solvent – deep violet. These different colors arise as a result to ligand field interactions with d-orbitals of iodine. Ligand field interactions are discussed in Chemsitry 203.
Iodine was first discovered in 1811 and named for its beautiful violet color (iodes means violet in Greek). Iodine is frequently used as an antiseptic agent. Tincture of iodine is a solution of iodine in ethanol.
“One day in 1811, Courtois made a mistake. He added too much sulfuric acid to the mixture. He was amazed to see clouds of beautiful violet vapor rising from the mixture. He decided to study the new material. Eventually, he proved it was a new element. He named the element after its color. In Greek, the word iodes means ‘violet.’”
Read more about iodine at Chemsitry Explained.