Rare Earth Compounds and Their Material Applications

Except for a few that directly use rare earth metals, most of the rare earth materials use compounds of rare earth elements. With the rapid development of high and new technologies such as computers, optical fiber communications, superconductivity, aerospace, and atomic energy, rare earth elements and their compounds play an increasingly important role in these fields. There are many types of rare earth element compounds, and they are still increasing. Among the more than 26,000 existing rare earth compounds, there are nearly 4,000 rare earth inorganic compounds with determined structures.

Among dilute compounds, oxides and composite oxides are the most synthesized and used. Because rare earths have a strong affinity with oxygen, they are easy to synthesize in the air. Among oxygen-free rare earth compounds, halides and composite halides are the most synthesized and studied because they are raw materials for the preparation of other rare earth compounds and rare earth metals. In recent years, due to the need for the development of high-tech new materials, research on the synthesis and application of oxygen-free rare earth compounds such as rare earth sulfides, nitrides, and borides, as well as rare earth complexes, has been extensively carried out, and the scope is increasing day by day.