Formation of Complex Compounds
Transition metals are renowned for their ability to form complex compounds, which are defined as compounds consisting of a central metal ion surrounded by ligands, which can be anions or neutral molecules. This phenomenon is primarily attributed to the unique properties of transition metals, such as their smaller ionic sizes, greater positive charges, and the presence of d orbitals that can participate in bonding. Therefore, they can engage efficiently in complexation reactions.
The ability to form complexes grants transition metals a variety of characteristic properties, including varied coordination numbers and geometries, electronic configurations that allow for spectroscopic activity, and diverse reactivity. Common examples of complex compounds include [Fe(CN)6]^{3-} and [Cu(NH3)4]^{2+}. This capacity for forming complexes is important in both biological systems, for example, hemoglobin, and industrial applications, such as catalysts and batteries.