Sb2O3

Antimony trioxide, with the chemical formula Sb2O3, is an inorganic compound in which antimony is in the +3 oxidation state. It is the most common oxide of antimony and is widely used as a flame retardant additive, as well as in various industrial applications. In nature, Sb2O3 occurs as the minerals valentinite and senarmontite.

Sb2O3 is a white to pale yellow powder that is insoluble in water. It is stable in air and can exist in multiple crystalline forms, commonly referred to as alpha- and beta-Sb2O3, with the different forms exhibiting variations in color and stability. The material is typically prepared by the oxidation (roasting) of antimony-containing ores such as stibnite (Sb2S3) in air, which converts sulfur to sulfur dioxide and yields Sb2O3. It can also be produced from antimony metal or other antimony compounds.

The primary use of Sb2O3 is as a flame retardant synergist for halogenated polymers, such as polyvinyl chloride (PVC), where it helps reduce flammability in combination with halogen-based additives. Additional applications include use as an opacifier in glass and ceramic glazes and as a catalyst or processing aid in some polymer and chemical industries.

Safety considerations are important, as Sb2O3 is toxic in certain exposure scenarios. Inhalation of dust can irritate the respiratory tract, and prolonged or high-level exposure should be avoided through appropriate industrial hygiene measures and handling practices.