What is the structure of sulfur trioxide

Sulfur trioxide

Sulfur trioxide is one of the two oxides of sulfur. It belongs to the class of inorganic compounds and has the formula SO3. Another name is sulfur-VI-oxide.



Coordination: In the gaseous state, sulfur trioxide forms molecules with the formula SO3. They are flat, the sulfur atom is in the center, and the 3 oxygen atoms are arranged around the sulfur atom at the corners of an equilateral triangle. The angle between the bindings is exactly 120 °.

View: Start the Jsmol visualization by clicking the link under the sulfur trioxide molecule.

In the solid state there are no SO3–Molecules present. Sulfur trioxide then forms trimers of the formula S.3O9. In addition, as soon as traces of water come together with sulfur trioxide, two further modifications develop.

In the liquid state, both are SO3–Molecules as well as S3O9–Trimers available. When converting the trimers to SO3–Molecules, energy is consumed.

S.3O9 + 126 kJ → 3 SO3

Hence the proportion of SO3–The higher the temperature, the larger the molecules.

  • more about solid sulfur trioxide - coming soon

Manufacture and use

Sulfur trioxide does not occur naturally. It is made from sulfur dioxide. Most of the sulfur trioxide is immediately processed into sulfuric acid. You will soon find a detailed description of the processes for the production of sulfur trioxide and sulfuric acid on my website.

  • more about the production of sulfur trioxide and sulfuric acid - coming soon

Physical Properties

  • Melting point: 16.86 ° C
  • Boiling point: 44.45 ° C
  • Density in the liquid state at 25 ° C: 1.903 g / cm3
  • CAS no. : 7446-11-9



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