Hard to Get At

Dysprosium's name is a rare instance of a chemist commemorating his own frustration. Lecoq de Boisbaudran reached the element only after repeated fractional precipitations, coaxing it apart from its near-identical neighbours, and he marked the ordeal by naming it the hard-to-get-at one. The name belongs to the wider story of the rare earths, whose chemical sameness made their separation one of the most laborious tasks in the history of chemistry, sometimes requiring hundreds or thousands of repeated crystallisations. Dysprosium has no ancient, mythological or alchemical association; its Greek name is a laboratory joke about the sheer obstinacy of the substance, now attached to an element that has become quietly essential to the magnets of electric motors and wind turbines.

Lecoq de Boisbaudran was among the most prolific element-hunters of the century, personally credited with the discovery of gallium in 1875, samarium in 1879 and dysprosium in 1886, a run matched by very few chemists before or since and made possible by his own refinements to spectroscopic and fractional-crystallisation technique. His patience with dysprosium in particular, requiring dozens of repeated precipitations to isolate a barely detectable residue, became something of a legend among later rare-earth chemists confronting their own stubborn separations.