What element has the symbol 'Ir'?

The story behind the answer

Ir stands for Iridium, element 77. Iron’s symbol is Fe (from ferrum), Indium is In, and “Irseum” isn’t an element. Iridium is a member of the platinum group metals, famed for being one of the densest and most corrosion-resistant elements.

Discovered in 1803 by Smithson Tennant in platinum ores, it was named after Iris, the rainbow goddess, because its compounds show vivid colors. You’ll find iridium in spark plugs, crucibles, pen tips, and durable alloys. Memory tip: Fe = iron, In = indium, so Ir must be iridium—think “Iris → Ir → Iridium.”