The element with atomic number 61 named after the fire-stealing Titan is promethium.
Promethium is a radioactive lanthanide with the symbol Pm. Its name honours Prometheus, the figure in Greek mythology who stole fire from Mount Olympus and gave it to humanity. The name was chosen to represent both the daring of scientific discovery and the possible misuse of human knowledge. The spelling was later standardized from the proposed “prometheum” to “promethium.”
Element 61 was predicted long before it was securely identified. In 1914, Henry Moseley’s measurements showed that atomic number 61 was missing from the periodic table between neodymium and samarium. Several earlier claims, including “florentium” and “illinium,” proved incorrect. Promethium was finally produced and characterized in 1945 at Oak Ridge National Laboratory by Jacob Marinsky, Lawrence Glendenin and Charles Coryell, using uranium fission products.
All promethium isotopes are radioactive, so it has no stable form. Only trace amounts occur naturally, and most usable promethium is produced artificially. Promethium-147 has applications in luminous paint, thickness gauges and experimental nuclear batteries. A common mix-up is technetium, another radioactive element bordered by stable neighbors, but technetium is atomic number 43.