Answer:
Examples of complex compound include potassium ferrocyanide K4[Fe(CN)6] and potassium ferricyanide K3[Fe(CN)6]. Other examples include pentaamine chloro cobalt(III) chloride [Co(NH)5Cl]Cl2 and dichlorobis platinum(IV) nitrate [Pt(en)2Cl2](NO3)2.
There are only 2 atoms in an Oxygen molecule
Covalent bond is the type of bond which involves the sharing of valence electrons between two atoms.
This bond usually arises from the equal attraction of the nuclei of the two atoms for the electrons shared.
Ionic bond, on the other hand, arises due to the transfer of electrons from the valence shell of one atom to the valence shell of the other.