Give the oxidation state, d-orbital occupation and coordination number of the central metal ion in the following complexes: `cis- [Cr(en)_2Cl_2]Cl`

Explanation

To solve the problem, we need to determine the oxidation state, d-orbital occupation, and coordination number of the central metal ion (chromium) in the complex `cis-[Cr(en)2Cl2]Cl`. Let's go through the solution step by step.

### Step 1: Determine the Oxidation State of Chromium

1. **Identify the ligands and their charges**:
- Ethylenediamine (en) is a neutral ligand, so it contributes 0 to the charge.
- Chloride ion (Cl) has a charge of -1. In the complex, there are 2 chloride ions inside the brackets and 1 outside.
- Therefore, the total contribution from chloride ions is:
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