Ionic bonds are formed when an electron (or electrons) are actually transferred from one atom to another. Each (former) atom is made into an ion and the ionic attraction between + and - ions is the bond. However, bonds can also form by sharing electrons and these are called covalent bonds. Yes, :N:::N: is a covalent bond (technically three covalent bonds) as is H-H, Cl-Cl and all other diatomic species. But covalent bonds can form between different atoms also, such as CH4, CH3Cl, etc.