Swedish-German pharmacist and chemist · 1742–1786
Carl Wilhelm Scheele
Carl Wilhelm Scheele was a pharmacist in small Swedish towns who discovered more new substances than almost any chemist of his century. He found oxygen before anyone else and identified chlorine, barium and molybdenum, but bad luck with publishers cost him much of the credit.
- Elements credited
- 4
- Discoveries
- 1772–1778
- Co-discoverers
- 1
- Where
- Sweden and England; Sweden
Discovery timeline
1772 · Sweden
Barium is a soft, silvery alkaline earth metal. Its insoluble sulfate lets doctors see the digestive tract on X-rays.
1774 · Sweden and England
Oxygen is a highly reactive gas that makes up 21% of the air and nearly half of Earth’s crust by mass. Animals need it to release energy from food.
1774 · Sweden
Chlorine is a toxic yellow-green halogen gas. Combined with sodium, it forms table salt; on its own it is a powerful disinfectant.
1778 · Sweden
Molybdenum is a silvery metal with one of the highest melting points of all elements. It strengthens steel at high temperatures.
The discoveries
Scheele produced oxygen by heating mercuric oxide, saltpetre and other compounds around 1771 to 1772, and called it “fire air” because candles burned brightly in it. His book describing the work was delayed at the printer until 1777, by which time Joseph Priestley had published his own discovery. The two are now usually credited together.
In 1774 he made chlorine by treating pyrolusite, a manganese ore, with hydrochloric acid, and described its choking smell and its power to bleach. He believed it was a compound containing oxygen. Humphry Davy showed in 1810 that it was an element.
The same pyrolusite work led him to a new earth, baryta, the oxide of barium, though he could not isolate the metal. In 1778 he showed that the mineral molybdenite contained a distinct new element rather than lead or graphite. In each case others later produced the pure element, but Scheele recognised it first.
Life and career
Scheele was born in Stralsund, then part of Swedish Pomerania, and was apprenticed to an apothecary in Gothenburg at 14. He taught himself chemistry from books and experiments, working in pharmacies in Malmö, Stockholm and Uppsala.
In Uppsala he befriended Johan Gottlieb Gahn and Torbern Bergman, who helped bring his work to wider attention. He spent his last years running a pharmacy in Köping and turned down offers of university posts. He died at 43, possibly from long exposure to the toxic substances he routinely smelled and tasted.
Also known for
- First to isolate tartaric, citric, lactic, oxalic and uric acids
- Prepared hydrogen cyanide and hydrogen fluoride
- Scheele’s green, a copper arsenite pigment