How is that silicon atoms can have a co-ordination number more than four but carbon atoms cannot?

How is that silicon atoms can have a co-ordination number more than fo

1.	How is that silicon atoms can have a co-ordination number more than four but carbon atoms cannot?
Answer» Silicon has vacant d-orbitals, therefore, it can have coordination number more than four but carbon cannot have because it does not have vacant d-orbitals.