|Geneva, Paris—Jean Charles Galissard de Marignac, Georges Urbain elements|
Jean Charles Galissard de Marignac split terbia into terbia and (he called it) ytterbia, the oxide of ytterbium, the fourth element named after Ytterby, Sweden. * Years later, Georges Urbain isolated from ytterbium oxide two elements— neoytterbia, later named ytterbium, and lutecia, later named lutetium.
Atomic number 70
A little ytterbium-169 is a radiation source in portable X-ray machines. A little ytterbium improves the mechanical properties of stainless steel. A little ytterbium helps make an efficient laser with a short pulse.
Ytterbium occurs naturally as a mixture of seven isotopes. All seven exist in exceedingly small quantities. Exceedingly rare qualities, rare things matter a lot.