French chemist and spectroscopist · 1838–1912
Paul-Émile Lecoq de Boisbaudran
Paul-Émile Lecoq de Boisbaudran discovered gallium in 1875, the first of Mendeleev’s predicted elements to be found. He went on to identify samarium and dysprosium, mostly in a private laboratory in his family’s cognac house.
- Elements credited
- 3
- Discoveries
- 1875–1886
- Co-discoverers
- 0
- Where
- France
Discovery timeline
1875 · France
Gallium is a soft, silvery metal that melts in your hand at 29.8 °C. Its compounds are essential in LEDs and high-speed electronics.
1879 · France
Samarium is a silvery rare-earth metal used in heat-resistant magnets and in cancer pain relief.
1886 · France
Dysprosium is a rare-earth metal added to neodymium magnets so they keep working at high temperatures.
The discoveries
Lecoq spent years studying the spectra of elements and looking for patterns. In 1875 he saw two violet lines that matched nothing known in a zinc ore from the Pyrenees. Within weeks he had isolated the new metal and named it gallium after Gaul, the Latin name for France.
Mendeleev immediately claimed it as his “eka-aluminium” and pointed out that the measured density was too low. Lecoq rechecked his purified sample and found Mendeleev was right. It was a dramatic confirmation of the periodic table.
He then turned to the rare earths. He identified samarium in 1879 in the mineral samarskite, and in 1886 separated dysprosium from holmium after more than thirty attempts. He named it from the Greek dysprositos, “hard to get at”.
Life and career
Lecoq was born in Cognac to a wine-making family and educated largely at home. He worked in the family business while carrying out his research in his own laboratory, without a university post for most of his career.
His book on spectra, published in 1874, became a standard reference. He was elected a corresponding member of the French Academy of Sciences.