Element 53 · Halogen
Iodine
Iodine is essential to thyroid function — and used in medical imaging contrast agents and antiseptics.
Element Facts
SYMBOL
I
ATOMIC NO.
53
ATOMIC WEIGHT
126.904
CATEGORY
Halogen
PERIOD
Period 5
GROUP
Group 17
Background
Iodine was discovered in 1811 by Bernard Courtois, a French manufacturer of saltpetre, who noticed a purple vapour rising when he accidentally added too much sulphuric acid to seaweed ash. It was named for the characteristic violet colour of its vapour (from the Greek “iodes”). By the 1820s, Lugol’s solution (iodine in potassium iodide) was used as an antiseptic. Iodised salt was introduced from the 1920s to prevent goitre, a then-widespread iodine deficiency disease.
Industrial Uses
Major current uses include antiseptics (betadine/povidone-iodine), thyroid disease treatment and diagnosis, polarising films for LCD screens (a large and growing application), X-ray contrast agents (iodinated contrast media for CT and angiography), and as a catalyst in industrial acetic acid production.
Scrap Viability
Why QuickStop Metals doesn’t buy Iodine:
Iodine is a non-metallic halogen — a dark grey-purple solid that sublimes easily to a purple gas. It is not a metal and does not appear in scrap metal streams. Iodine is produced from Chilean caliche ore and underground brine wells in Japan and the USA.
What It's Worth
Iodine trades at approximately £15–40/kg on commodity markets, with prices subject to Chilean export policy and LCD screen demand. Not a scrap commodity.