Yttrium, atomic no. 39, symbol Y, weight at 88.91, has the highest thermo-dynamic affinity for oxygen of any element, this characteristic is the basis for many of its applications. While not part of the rare earth series, it resembles the heavy rare earths which are sometimes referred to as the yttrics for this reason.
Some of the many applications of yttrium include in ceramics for crucibles for molten reactive metals, in florescent lighting phosphors, computer displays and automotive fuel consumption sensors.
Yttria stabilized zirconium oxide are used in high temperature applications, such as in thermal plasma sprays to protect aerospace high temperature surfaces.
Crystals of the yttrium-iron-garnet (YIG) variety are essential to microwave communication equipment.