1811 Iodine

The book of science

Tom Sharp

DijonBernard Courtois elements Iodine


It was an accident, but Bernard Courtois realized he had found something new, an element that no one else had previously described. Courtois was processing seaweed for sodium carbonate, but he added too much acid, making a cloud of purple vapor that crystallized on cold surfaces. Courtois gave samples to Ampère and Gay-Lussac, who confirmed the discovery, and Ampère gave some to Davy, who named it iodine.

Atomic number 53

Dietary supplement (essential for life) Disinfectant (antibacterial and antiviral) Staining (for starch or cancerous tissue) And protecting the thyroid from nuclear fallout (just in case)

Stuff that stings

A glass rod was attached to the lid of the little bottle of tincture of iodine. Mom would wipe its cold glass knob over a cut to apply the rusty iodine. That stuff would sting like heck. Man, that stuff would sting like heck.

Iodine is named after the color of its violet vapor. Tincture of iodine for topical application (2% in ethanol and water) had more of a rusty color.

See also in The book of science:

Readings on wikipedia:

Other readings:

  • Iodine,” Elementymology & Elements Multidict, by Peter van der Krogt