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Antimony trioxide

CAS Number
1309-64-4
EC Number
215-175-0
Chemical Formula
O3Sb2
Molecular Weight
291.52 g/mol

Description

Antimony trioxide (CAS 1309-64-4 ), also known as Flowers of Antimony, is a flame retardant synergist used across plastics, textiles, and industrial materials. It does not act as a standalone flame retardant. Instead, it amplifies the performance of halogenated flame retardant systems, allowing formulators to achieve target fire ratings at lower total additive loadings. In plastics and polymers, it is compounded with brominated or chlorinated flame retardants. This process helps materials meet UL 94 and other flammability standards in wire insulation, connectors, and housings. Textile and fabric coatings for automotive interiors, upholstery, and protective workwear rely on it to pass certifications. In construction materials, it is incorporated into PVC profiles, roofing membranes, and wall panels where building codes mandate flame resistance. Electronics manufacturers use it in printed circuit board laminates and encapsulant compounds. These applications help to control flame spread in high-density assemblies. Antimony trioxide is supplied as a fine white powder in standard and high-purity grades for various industrial needs. Technical and flame retardant grades are the most common commercial forms, with particle size specifications varying by application. Finer grades are preferred for film and fiber applications. Bulk bags and small-pack options are standard across the supply chain. This ensures that manufacturers can source the material in the quantities required for their specific production processes. Contact us for supply of Antimony trioxide Request Quote

Other Names (Synonyms)

Flowers of Antimony | Antimony(III) oxide | Antimony sesquioxide | Antimonous oxide | Diantimony trioxide | Antimonious oxide | Exitelite | Timonox

Key Technical Features

  • High Purity Grade standard
  • Consistent Batch Quality
  • Full Regulatory & REACH Support
  • Global Logistics Network enabled

Physical Properties

Melting Point655 °C
Boiling Point1425 °C
Density5.2 g/cm³ (solid)
Flash Point1550°C subl.
AppearanceWhite or gray mineral, sometimes pale red, white streak and adamantine or silky luster. Mohs hardness 2–3.
ColorWhite
Odorwh. cubic or orthorhombic cryst., odorless
Formpowder
Water SolubilitySlightly soluble. <0.1 g/100 mL at 20 ºC
Vapor Pressure13.3 hPa (660 °C)

Safety & Handling

Warning
GHS08· Health HazardGHS09· EnvironmentGHS07· Irritant

Hazard Statements

H351Suspected of causing cancer
H350May cause cancer
H401Toxic to aquatic life
H411Toxic to aquatic life with long lasting effects
H302Harmful if swallowed
H371May cause damage to organs
H372Causes damage to organs through prolonged or repeated exposure
H303May be harmful if swallowed
H320Causes eye irritation
H360May damage fertility or the unborn child
H370Causes damage to organs
H402Harmful to aquatic life
H412Harmful to aquatic life with long lasting effects

Trade & Regulatory

HS Code28258000
Storage Class13 - Non Combustible Solids
WGK (Germany)2