Radium: Chloride Electrolysed onto Mercury, Amalgam Heated to 700 °C in Hydrogen (Curie and Debierne, 1910)

Marie Curie and André Debierne made the first radium metal from a tenth of a gram of its chloride: electrolysis into a mercury cathode gave a radium amalgam, and gentle heating in hydrogen drove the mercury off. Result: a little bright white radium metal, melting near 700 °C. Source: Thorpe, Dictionary of Applied Chemistry vol. 4 (1912), RADIUM, p. 545 (Curie and Debierne, Compt. rend. 1910). Radium is intensely radioactive and a poison; mercury vapour is poisonous. Picture drawn by Youblob.