A maximum of four bonds can be used between two atoms.
Step-by-step explanation:
Ionic bond is one of the strongest bond used in chemical reaction where the valence electrons are bonded and shared between the atoms. Sometimes four covalent bonds between two atoms might make them unstable as the bonds are formed in their outermost shell to make them to form or complete a total of 8 in their shell. For example carbon has 3 as maximum.