Question

Purest form of Solid Sulphur trioxide exists as:

• A. Dimer
• B. Trimer
• C. Both a and b
• D. None of these

Answer 1

The correct option is B Trimer

The structure of solid $S{O}_3$ is surprisingly complex. When the gas is condensed into absolutely pure solid form, the compound exists as a trimer.

Now what would be the geometry of the of the each of the elements in the six-membered ring?
This ice-like pure $(S{O}_3{)}_3$ is called $\gamma$ - $S{O}_3$ Other crystalline forms of solid (of course!!) $S{O}_3$ exists as well.
They might be long-chain solid polymeric compounds of the form $HO-(S{O}_3{)}_n-OH$ such that n is a very big number like ${10}^5$.