Curated playlist
Rare earth elements
- EuropiumEuropium is a metal so soft you can slice it with a kitchen knife. It also glows red inside color television screens.
- DysprosiumDysprosium got its name from a Greek word meaning "hard to get." A chemist needed over thirty tries in 1886.
- CeriumPrimo Levi bartered a stash of lighter-flint alloy for food at Auschwitz.
- TerbiumTwo elements, erbium and terbium, have had their names switched since the 1800s. Nobody has corrected it.
- YtterbiumIn 2013, two ytterbium atomic clocks set a record for stability.
- LanthanumLanthanum is named for the Greek word for "lie hidden". Carl Gustaf Mosander found it in 1839 inside cerium nitrate.
- PraseodymiumPraseodymium spent decades hidden inside a supposed element called didymium. An Austrian chemist split it in 1885.
- ErbiumErbium, a rare metal, turns water rose-pink when its ions dissolve. It is used inside fiber-optic cables.
- NeodymiumNeodymium hid inside another metal for decades. Chemists took it for one element, didymium, until 1885.
- ScandiumScandium is about as common in Earth's crust as cobalt. Yet only 15 to 20 tonnes of its oxide are traded a year.
- YttriumA Swedish village called Ytterby lent its name to four chemical elements. It began with one heavy black rock.
- GadoliniumGadolinium is toxic as a free ion, yet doctors inject it into veins. A protective wrapping makes it safe enough for MRI.
- SamariumSamarium is the first element named, indirectly, after a person. The honor went to a Russian mining chief.
- Rare-earth elementThe rare-earth elements are a family of 17 soft, silvery-white metals, and the first thing to know about them is that their name is misleading. Cerium, the most plentiful member, makes up 68 parts per million of Earth's crust. That ranks…