Characteristic

Antimony(III) oxide is the inorganic compound with the formula Sb₂O₃. It is the most important commercial compound of antimony. It is found in nature as the minerals valentinite and senarmontite. Like most polymeric oxides, Sb₂O₃ dissolves in aqueous solutions with hydrolysis.

Chemical formula：Sb₂O₃

Molar mass：291.518 g/mol

Appearance：white solid

Odor：odorless

Density：5.2 g/cm³, α-form

               5.67 g/cm³ β-form

Melting point：656 °C (1,213 °F; 929 K)

Boiling point：1,425 °C (2,597 °F; 1,698 K) (sublimes)

Solubility in water：370 ± 37 µg/L between 20.8°C and 22.9°C

Solubility：soluble in acid

Magnetic susceptibility (χ)：-69.4·10⁻⁶ cm3/mol

Refractive index (nD)：2.087, α-form

                                     2.35, β-form

Crystal structure：cubic (α)<570 °C

                              orthorhombic (β) >570 °C

Application

The annual consumption of antimony(III) oxide in the United States and Europe is approximately 10,000 and 25,000 tonnes, respectively. The main application is as flame retardant synergist in combination with halogenated materials. The combination of the halides and the antimony is key to the flame-retardant action for polymers, helping to form less flammable chars. Such flame retardants are found in electrical apparatuses, textiles, leather, and coatings.

Other applications:

Antimony(III) oxide is an opacifying agent for glasses, ceramics and enamels.

Some specialty pigments contain antimony.

Antimony(III) oxide is a useful catalyst in the production of polyethylene terephthalate (PET plastic) and the vulcanization of rubber.

Sb2O3_MSDS.pdf