GROUP 3 TRANSITION METAL

Yttrium (pronounced it-ree-um) is formally included among the rare-earth elements but isn’t particularly rare; in fact, it’s more abundant than silver and lead. But its chemical properties are similar to rare-earths, and it tends to exist alongside them in minerals. You could, perhaps, think of yttrium as a rare-earth “wannabe” or “groupie”! See “Scandium, Sc” on page 60 for more on the rare earths.

Yttrium was discovered as yttrium oxide (Y₂O₃) in a coal-like mineral from an old quarry seam near the small Swedish village of Ytterby, located on an island in the Stockholm archipelago. Three more rare-earth elements hidden within the oxide were subsequently discovered and were also named in honor of their Swedish “birthplace”: erbium (Er), terbium (Tb), and ytterbium (Yb).

Crystals of yttrium aluminum garnet (YAG) doped with neodymium provide the solid-state laser source for a class of high-powered lasers capable of cutting and drilling through metals.

Yttrium oxide (Y₂O₃) helps to improve the heat- and shock-resistance of glass.

When the mixed oxide that yttrium forms with barium and copper is cooled with liquid nitrogen to –196°C, it displays superconducting properties (that is, it conducts electricity without losing energy). It’s better known by its abbreviated names 1-2-3 and YBCO, which are derived from its formula, YBa₂Cu₃O_7–9.

Yttrium has only one naturally occurring isotope, yttrium-89. But a radioactive isotope, yttrium-90, is formed when strontium-90 decays radioactively (with potentially serious consequences—see “Strontium, Sr” on page 111). ⁹⁰Y undergoes a similar radioactive beta decay. In this process, the transformation of one of ⁹⁰Y’s neutrons to a proton is accompanied by the emission of a high-speed electron, also known as a beta particle. Due to ⁹⁰Y’s relatively short half-life of approximately 64 hours, its beta particles have been harnessed in a controlled manner to treat various cancers by landing “radioactive knockout punches” on cancerous cells.