Question

Determine the formal charge of B in the compound B(OH) 3

Answer 1

The dot structure of boric acid is

The formal charge is

$$FC=\text{val. electrons}-\text{unbond.electrons}-\\-1/2\text{ bonded electrons}.$$

For boron in the diagram, we have 3 valence electrons, 0 unbonded electrons, and 6 bonded electrons. This gives us the formal charge of

$$FC=3-0-1/2\cdot6=0.$$