What is Sulfur Trioxide?
Sulfur trioxide is a chemical compound which is represented by chemical formula SO3. Sulfur trioxide exists in a number of modifications that differ in molecular species and crystalline form. In its liquid for it is colourless and fumes in air at ambient conditions. It is a highly reactive substance and a strong oxidising agent and it also acts as a fire hazard. It is thermodynamically unstable compound with respect to selenium dioxide.
Other names – Sulfuric anhydride
| SO3 | Sulfur Trioxide |
| Density | 1.92 g/cm³ |
| Molecular Weight/ Molar Mass | 80.066 g/mol |
| Boiling Point | 44.9 °C |
| Melting Point | 16.9 °C |
| Chemical Formula | SO3 |
Sulfur Trioxide Structure – SO3
Physical Properties of Sulfur Trioxide – SO3
| Odour | No odour |
| Appearance | Colourless to white crystalline solid |
| Covalently-Bonded Unit | 1 |
| Complexity | 61.8 |
| Hydrogen Bond Acceptor | 3 |
| Solubility | Soluble in water. |
Chemical Properties of Sulfur Trioxide – SO3
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- Sulfur trioxide reacts with water forming sulfuric acid. The chemical equation is given below.
SO3 + H2O → H2SO4
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- Sulfur trioxide reacts with a base sodium hydroxide forms sodium hydrogen phosphate. The chemical equation is given below.
SO3 + NaOH → NaHSO4
Uses of Sulfur Trioxide – SO3
- Used as a bleaching agent to remove residual hydrogen peroxide, or as a digesting agent to separate pulp from lignin.
- Used as a catalyst in the oxidation reaction of sulfur dioxide to sulfur trioxide.
- It is a strong inorganic acid mists containing sulfuric acid used in industry or in production of commercial products.
- Used as an essential reagent in sulfonation reaction.
- Used in the manufacture of photoelectric cells and solar energy devices.
