Chemical formula Y2O3, white slightly yellow powder, insoluble in water and alkali, soluble in acid. Mainly used for manufacturing magnetic materials for microwave and important materials for military use (single crystal; yttrium iron garnet, yttrium aluminum garnet and other composite oxides), it is also used as an additive for optical glass, ceramic materials, high brightness fluorescent powder for large screen televisions, and other picture tube coatings.