Question

Which of the following structures is the most preferred and hence of lowest energy for $S{O}_3$ ?

• A.
• B.
• C.
• D.

Answer 1

Answer: (D)

The lowest energy structure for a compound would be the one that has the smallest formal charges on its atoms. The formal charge is calculated using the formula:

Formal charge $=$ Total number of valence electrons $-$ Non-bonding electrons $-\frac{1}{2}\times$
Bonding electrons
Thus, for the structure of $S{O}_3$ given in option $A$, the formal charge can be calculated as $=6-4-\frac{1}{2}\times 4=0$
Thus, this structure has the lowest energy.