Yttrium is a Block D, Group 3, Period 5 element. The electronic configuration is [Kr] 4d¹ 5s². In its elemental form yttrium's CAS number is 7440-65-5. The yttrium atom has a radius of 177.6.pm and it's Van der Waals radius is 200.pm. Yttrium 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. Another unique characteristic derives from its ability to form crystals with useful properties. Yttrium is available as metal and compounds with purities from 99% to 99.999% (ACS grade to ultra high purity); metals in the form of foil, sputtering target, and rod, and compounds as submicron and nanopowder. 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 and as an electrolyte in solid oxide fuel cells.

Zirconium is a Block D, Group 4, Period 5 element. The electronic configuration is [Kr] 4d² 5s². In its elemental form zirconium's CAS number is 7440-67-7. The zirconium atom has a radius of 159.pm and it's Van der Waals radius is 200.pm. Zirconium is primarily used in it's oxide or zirconia form. Zirconium dioxide has a high melting point (2,700° C) and a low thermal conductivity. Its polymorphism, however, restricts its widespread use in ceramic industry. During a heating process, zirconia will undergo a phase transformation process. The change in volume associated with this transformation makes the usage of pure zirconia in many applications impossible. Addition of some oxides, such as CaO, MgO, and Y2O3, into the zirconia structure in a certain degree results in a solid solution, which is a cubic form and has no phase transformation during heating and cooling. This solid solution material is termed as stabilized zirconia, a valuable refractory. Stabilized zirconia is used as a grinding media and engineering ceramics due to its increased hardness and high thermal shock resistivity. Stabilized zirconia is also used in applications such as oxygen sensors and solid oxide fuel cells due to its high oxygen ion conductivity.