In an octahedral coordination complex, the crystal field splitting occurs due to the interaction between the central metal ion and the surrounding ligands. The ligands' electric field causes the d-orbitals of the metal ion to split into two energy levels: the lower energy t2g orbitals dxy, dyz, and dxz and the higher energy eg orbitals dx^2-y^2 and dz^2 .In the case of a complex with four chlorine ligands and two water ligands, we have a mixed-ligand octahedral complex. The crystal field splitting diagram will be influenced by the relative strengths of the ligands. Chloride ions Cl- are generally considered weaker field ligands than water molecules H2O . This means that the splitting of the d-orbitals will be less pronounced than in a complex with six strong field ligands.The crystal field splitting diagram for this complex will show the t2g orbitals at a lower energy level and the eg orbitals at a higher energy level. However, the energy difference between the two sets of orbitals o will be smaller than in a complex with six strong field ligands.The crystal field theory can help explain the observed spectroscopic and magnetic properties of this complex. The spectroscopic properties are related to the electronic transitions between the t2g and eg orbitals. The energy difference between these orbitals o determines the wavelength of light absorbed during these transitions. A smaller o will result in the absorption of lower energy longer wavelength light, which may lead to a different color for the complex compared to a similar complex with six strong field ligands.The magnetic properties of the complex are related to the presence of unpaired electrons in the d-orbitals. If the energy difference o is small, it is more likely that electrons will occupy the higher energy eg orbitals, resulting in unpaired electrons and a paramagnetic complex. If the energy difference o is large, electrons will preferentially occupy the lower energy t2g orbitals, pairing up and resulting in a diamagnetic complex.In summary, the crystal field splitting diagram for an octahedral coordination complex with four chlorine ligands and two water ligands will show a smaller energy difference between the t2g and eg orbitals compared to a complex with six strong field ligands. This difference in energy levels can help explain the observed spectroscopic and magnetic properties of the complex.