Paul-Émile Lecoq de Boisbaudran

2026-01-21 09:30:57

Paul-Émile Lecoq de Boisbaudran (Cognac, France, April 18, 1838 – May 28, 1912, Paris, France) was a French chemist who discovered gallium, the element predicted by Mendeleev. His primary work focused on spectroscopy and its application to rare earth elements. He analyzed the spectra of 35 elements using a Bunsen burner, an electric discharge, or both to induce luminescence, thereby discovering the lanthanides – samarium (1880), dysprosium (1886), and europium (1890). He isolated gadolinium (1885), an element previously discovered by J.-C. Marignac. He obtained (1875) several milligrams of gallium chloride from a sample of mineral ore and found that this substance produced new spectral lines. He calculated the atomic mass of gallium to be 69.86, which is very close to the currently accepted mass of 69.723(1).