Samarium

Samarium was first detected in 1879 by the French chemist Paul-Emile Lecoq de Boisbaudran, in the mineral samarskite. He named it after the mineral, which in turn had been named for Vasili Samarsky-Bykhovets, a Russian mining official who had granted access to the ore. Samarium is a moderately hard, silvery rare-earth metal, valued for samarium-cobalt magnets that keep their strength at high temperatures and for its use in cancer treatment. Such magnets hold their power where others fail in heat, suiting them to aircraft and military hardware, and samarium also serves as a neutron absorber in reactors, as a catalyst, and, as a radioactive isotope, in the relief of cancer pain.

In reactor physics samarium-149, a stable fission product, behaves as a neutron poison much like the more famous xenon-135, gradually building up in a reactor's fuel and absorbing neutrons that would otherwise sustain the chain reaction, a slow-acting effect engineers must account for over a reactor's operating life quite separately from samarium's own deliberate use as a shielding and control material. Samarium-153, a different radioactive isotope of the same element, is injected directly into patients as a targeted treatment that relieves pain from cancer that has spread to bone.

Samarium holds a small distinction in the history of nomenclature: through the mineral samarskite, it became the first element whose name honours a specific, named individual, the mine official Colonel Samarsky, even if only at one remove and by accident of the mineral's naming. This preceded the more deliberate personal namings of gadolinium, for the chemist Gadolin, and of the many later elements commemorating scientists. Samarium itself has no mythological or alchemical tradition, being a product of nineteenth-century rare-earth chemistry, but its name quietly opened the door to the long modern practice of writing human names into the periodic table, a practice that would eventually crowd the heaviest elements with the names of physicists and their laboratories.

Samarsky-Bykhovets himself was not a scientist but a Russian army colonel and mining administrator, whose sole connection to chemistry was authorising a German mineralogist's access to a particular ore deposit in the Urals, an administrative courtesy that nonetheless secured him permanent, if largely accidental, remembrance in the periodic table. The precedent proved consequential: once chemists grew comfortable naming elements for individuals rather than only places, planets or myths, the practice accelerated rapidly through the following century, especially among the heaviest synthetic elements.