Promethium

Uses

Because promethium doesn’t occur naturally in any usable quantity, all of it used today is produced artificially, typically as a byproduct of nuclear reactor operation. Its most practical application takes advantage of the steady, low-energy radiation given off by the isotope promethium-147: it has been used in luminous paints and dials as a safer substitute for older radium-based formulas, and in betavoltaic devices, effectively long-life nuclear batteries, that convert its radioactive decay directly into a small but extremely durable electric current for equipment that needs power for years without maintenance.

Beyond these specialized uses, promethium hasn’t found the broad industrial role that many of its lanthanide neighbors have, largely because its radioactivity and scarcity make it far more difficult and costly to work with.

History

Promethium was first produced and positively identified in 1945 by American chemists Jacob A. Marinsky, Lawrence E. Glendenin and Charles D. Coryell at Oak Ridge National Laboratory, who isolated it from the fission products created inside a nuclear reactor. Its existence had actually been predicted years earlier, since it was the one missing element in the lanthanide row of the periodic table, but because none of its isotopes are stable, no one had been able to find it occurring naturally. The team named it promethium after Prometheus, the Titan of Greek mythology who gave fire to humanity, a name meant to capture both the achievement of nuclear science and the caution its power demands.