Samarium (Sm)

Samarium is the chemical element with atomic number 62 and symbol $\mathrm{Sm}$. It is a lanthanide. Samarium-cobalt alloys provide strong permanent magnets. It also has useful $+2$ and $+3$ chemistry, illustrating that the common trivalent pattern of the lanthanides has chemically important exceptions.^[ref]

A stable samarium isotope used as the nuclear absorber in the Goldhaber experiment.