Strontium: Mercury-Cathode Amalgam Turned to Hydride and Distilled in Vacuo (Guntz and Roederer, Roscoe 1913)

Strontium chloride solution is electrolysed onto a mercury cathode, giving strontium amalgam. Heating it in vacuum and then in hydrogen drives off the mercury and leaves strontium hydride, which breaks down in vacuum at red heat; the strontium boils off and condenses on a water-cooled steel tube. Result: silver-white strontium, 98.6-99 % pure (99.4 % after a second distillation). Source: Guntz and Roederer (1906), in Roscoe and Schorlemmer, A Treatise on Chemistry vol. 2 (1913), pp. 595-596. Not given: current, anode, amounts. Mercury vapour is poisonous; the fine metal catches fire in air. Picture drawn by Youblob.