It is appropriate to form double or triple bonds in a Lewis structure when four or six electrons are shared.
A Lewis structure is a representation of a molecule using dots to show the valence electrons in the molecule. This dots are shown around the symbols of the elements.
However, in instances where four or six electrons are shared between bonding atoms, a double or triple bond is used. A double bond means that four electrons are shared. A triple bond means that six electrons are shared.
