Question

What is the formal charge of carbon atom in the lewis structure of carbonyl sulfide (`OCS`)?

Answer 1

To a first approx. the Lewis structure of carbonyl sulfide is the same as that of carbon dioxide. The formal charge of `C` is thus ZERO.

Explanation:

Given an `O=C=O`, or `S=C=O` Lewis structure, there are 8 bonding electrons around carbon, 4 of which this atom claims. And thus with 2 inner core electrons, the 6 electrons balance the nuclear charge to give a neutral carbon centre. Of course all the atoms in this molecule are formally neutral.

The `C=S` bond length is approx. `1.6xx10^-10*m`, the which is shorter than a regular `C-S` bond, approx. `1.8xx10^-10*m`.