Antimony trioxide (antimony(III) oxide)

Physical and chemical characteristics

Sb2O3 exists in more than one crystalline form (commonly described by mineral names) and shows weakly amphoteric behaviour: it is sparingly soluble in water but dissolves in strong acids and alkalis to give a range of antimony(III) species. Under strongly oxidizing conditions it can be converted to higher oxides of antimony. The material is used where a stable, low‑solubility oxide is required and is compatible with many polymer and glass matrices.

Production and occurrence

Commercial production typically starts from stibnite (antimony sulfide) which is roasted to yield the oxide and sulfur dioxide; metallic antimony can also be oxidized to produce Sb2O3. Natural occurrences and ore processing are the usual sources for industrial supplies. For mineral processing and refining context see descriptions of stibnite and ore treatment methods.

Uses and applications

• Flame retardant synergist: Sb2O3 is widely added with halogenated flame retardants to plastics, textiles and electronic components to enhance smoke suppression and flame‑retardant performance.
• Glass and ceramics: it acts as an opacifier and fining agent to remove bubbles and adjust optical properties in glass and glazes.
• Catalysis and polymers: antimony compounds serve as catalysts in some polymerizations and chemical syntheses, notably in the production of certain polyesters.
• Specialty uses: laboratory reagents, pigments and intermediates in producing other antimony chemicals.

Health, safety and environmental notes

Antimony trioxide is hazardous if inhaled or ingested and can irritate the eyes, skin and respiratory tract. Occupational exposure is controlled by dust suppression, ventilation and personal protective equipment. International authorities have examined its carcinogenic potential and it is handled with caution in regulatory frameworks; consult the relevant classification and material safety resources for up‑to‑date guidance. Environmental release should be minimized and waste managed according to local regulations.

For authoritative technical data and further chemical context see overviews of oxide chemistry and industrial chemical references. Practical distinctions include its difference from higher antimony oxides and from elemental antimony in behaviour, reactivity and applications.