Used in fiber optics to enhance the refractive index of glass, enabling efficient transmission of light signals over long distances. Commonly employed as a dopant in optical fibers for telecommunications and data transmission. Acts as a catalyst in polymerization reactions, particularly in the production of polyethylene terephthalate (PET) for plastics and polyester fibers. Utilized in infrared optics due to its transparency in the infrared spectrum, making it suitable for lenses and windows in thermal imaging devices. Investigated for use in semiconductor applications and solar cells for improving efficiency in photovoltaic systems.