Sulfur trioxide

Synonyms

Sulfan; Sulfur oxide; Sulfur trioxide, stabilized; Sulfuric anhydride; Sulfuric oxide; Sulphur trioxide; Sulfur trioxide, inhibited or Sulfur trioxide, stabilized; Sulfur trioxide, uninhibited; [ChemIDplus] UN1829

Category

Other Toxic Gases & Vapors

Description

Colorless to white solid that fumes in air at room temperature; [HSDB] Exists in 3 modifications; The alpha and beta forms are solids; mp = 62.3 and 32.5 deg C, respectively; The gamma form is a solid or liquid with a mp of 16.8 deg C; [Merck Index]

Sources/Uses

Used as a sulfonating agent in the production of detergents and an intermediate in the production of sulfuric acid and explosives; [HSDB]

Comments

Highly corrosive to skin; [Quick CPC] Can cause severe coughing at a concentration of 1 ppm; [HSDB] When dry, rapidly absorbs moisture from air evolving dense white fumes; Reacts explosively with water forming sulfuric acid; [Merck Index] A strong oxidant that poses a fire and explosion hazard on contact with organic materials; Corrosive to skin, eyes, and respiratory tract; Repeated or prolonged exposure to aerosol may cause effects to the lungs and erosion of teeth; [ICSC] Concentrations of 1 ppm may cause coughing, choking, and severe discomfort; Causes severe burns to skin and eyes; Inhalation causes severe irritation and may cause pulmonary edema; Causes erosion and discoloration of teeth; Health effects basically the same as those for sulfuric acid; [IUCLID] Causes diffuse hepatitis, changes in bronchi, and other endocrine changes in inhalation lethal-concentration studies of guinea pigs; [RTECS]
See "Sulfuric acid."

Biomedical References

Yes

263 mm Hg

LCLo (guinea pig) = 30 mg/m3/6hr

Explanatory Notes

Vapor pressures at 25 deg C: alpha = 73 mm Hg; beta = 344 mm Hg; gamma = 433 mm Hg; [Merck Index] VP = 263 at 25 deg C; [HSDB]

will not burn

2 mg/m3

10 mg/m3

120 mg/m3

Yes

Hepatoxic (a) from occupational exposure (secondary effect) or (b) in animal studies or in humans after ingestion

Skin burns

Diseases

Occupational diseases associated with exposure to this agent:

• Pneumonitis, toxic