How many pi bonds can the atom form?

1 Answer
Feb 27, 2017

Assuming the discussion is restricted to organic chemistry and we are talking about carbon, two pi bonds are possible.


Consider the triple bond in Ethyne

Carbon has four valence electrons so in order to make 4 bonds, it must hybridize its orbitals to make that possible. In this case, Carbon takes on an #sp# hybrid configuration in which one electron goes into each #sp# hybrid orbital and the other two each go into the unhybridized #p# orbitals.

The electrons in each carbon's #sp# orbital that face one another participate in a tight sigma bond. The electrons in the unhybridized #p# orbitals form a pi bond like a bridge.

Consider also #CO_2#

Carbon has the same #sp# hybridization here where the two #sp# orbitals participate in sigma bonds with the oxygen while each unhybridized #p# orbital forms a double bond with the adjacent oxygen.

While a quadruple bond is possible for coordination compounds with transition metals, here is no hybridization scheme that allows for a quadruple bond to form between two atoms in organic chemistry.