In the coordination compound Coen2Cl2Cl (en = ethylenediamine), the coordination number and oxidation number of the central atom are, respectively:

Coen2Cl2Cl(en) = ethylenediamine has two donor sites (en) = 4 donor sitesCl2=2 donor sites 6 donor sites (so, six coordination number). Coen2Cl2Cl↓x + 2 (0) + (- 3) = 0 (en) Neutral ligandx = + 3 oxidation state.