Question

When you draw Lewis structures of a compound, what will you do when you have some atom(s) do(es) not have an octet but you already use up all the valence electrons?

Answer 1

The cases where we do not have sufficient valence electrons on an atom to form an octet, we can use the dimers of these compounds to satisfy the valence electrons. This concept is used in boranes (compounds of boron with hydrogen) where the boron reacts with hydrgoen to give B₂H₆ and not BH₃ because BH₃ has only six electrons even after sharing the valence electrons with hydrogen.The formation of B2H6 satisfies the valence electrons for both the boron atoms.