In many cases, a negatively charged compound (ex Cl-) will interact with a positively charged metal (ex Fe2 ). Usually we would
consider this type of interaction to be ionic, but in the case of metals we do not. What type of bond is being formed when a ligand interacts with a metal and how could you know that the bond you are forming is that type of bond
An ionic bond occurs due to electrostatic attraction between a positively charged ion and a negatively charged ion.
A metal and a ligand are bound by a coordinate covalent bond or a dative bond. This bond occurs due to donation of electron pairs from ligands to available orbitals on metals.
The formation of coordinate bonds is evident when neutral molecules or negative ions with non bonding electrons donate same to empty metal orbitals. This is sometimes shown by an arrow pointing from the ligands to the metal center.
For instance; tetraammine copper II ion is formed when four ammonia molecules donate a lone pair each to available vacant orbitals of the copper metal center to form [Cu(NH3)4]^2+.
