The complexes in which the coordination sphere does not carry any charge are called neutral complexes.
Diamminedichloroplatinum(II): $\left[\mathrm{Pt}\left(\mathrm{NH}_3\right)_2 \mathrm{Cl}_2\right]$ is a neutral complex.
Pentamminecobalt(III) sulphate is a cationic complex,
Potassiumhexacyanoferrate(II) and Potassium trioxalatoaluminate(III) are anionic complexes.