Antimony(III) oxide finds use as flame retardant wherein it synergistically acts with halogenated materials. It is employed in opacifying glasses, ceramics and enamels. In the preparation of optical and ruby glass, antimony trioxide serves as a bubble remover. Further, it is a useful catalyst in the production of polyethylene terephthalate (PET plastic) and the vulcanization of rubber.

This Thermo Scientific Chemicals brand product was originally part of the Alfa Aesar product portfolio. Some documentation and label information may refer to the legacy brand. The original Alfa Aesar product / item code or SKU reference has not changed as a part of the brand transition to Thermo Scientific Chemicals.