Rare earth elements/metals are a collection of elements in the periodic that include the fifteen lanthanoids among others with similar chemical properties. These materials are found in relatively high concentrations in the earth’s crust, but are more difficult to mine and extract in comparison to transition metals. Separation of these elements is difficult due to the elements having similar chemical properties. Rare earth metals have a variety of uses; rare earth ions are used as the active ions in luminescent materials used in optoelectronics applications and phosphors with rare earth dopants are also widely used in cathode ray tube technology for example.
