# What is the number of valence electrons in this compound?

## What is the number of valence electrons in this compound? $\left[C o {\left(N {H}_{3}\right)}_{3} C {l}_{3}\right]$

Well, $\left[C o {\left(N {H}_{3}\right)}_{3} C {l}_{3}\right]$ is an 18 electron complex...
You gots a $C {o}^{3 +}$ centre...that's $\text{6 d-electrons}$, you got 3 ammonia donors...that's another 6 electrons...and another $3 \times C {l}^{-}$ ligands, each of which donates TWO electrons....that is 18 electrons in total....