Used as a key component in red phosphors for cathode ray tubes and LED displays, enabling bright red and white light emission. Widely applied in ceramics and glass manufacturing to enhance thermal stability and resistance to cracking under high temperatures. Serves as a stabilizer in zirconia-based materials, improving strength and durability for use in industrial coatings and cutting tools. Employed in the production of superconductors and advanced optical coatings due to its high refractive index and transparency in the infrared range. Also utilized in medical imaging and cancer treatment through yttrium-90 containing compounds derived from the oxide.