Inorganic chemistry and rare-earth separation · 1872–1938

Georges Urbain

Urbain worked in Paris on the last and hardest divisions in the rare-earth series, at the point where the differences between neighbouring elements are smallest and the number of crystallization cycles needed is largest. He was also among the chemists who had to accept an external verdict on their own results: when Moseley’s X-ray measurements gave each element a whole-number atomic number, they settled which of the many claimed rare earths were real and how many could still be missing. Urbain submitted samples for exactly that test.