Among the following, the maximum covalent character is shown by the compound

Options

A. `FeCl_2`
B. `SnCl_2`
C. `AlCl_3`
D. `MgCl_2`

Explanation

To determine which compound among the given options shows the maximum covalent character, we will apply Fajans' rule. This rule states that the covalent character of an ionic compound increases with the following factors:

1. **Smaller size of the cation**: A smaller cation can polarize the electron cloud of the anion more effectively.
2. **Larger size of the anion**: A larger anion is more easily polarized.
3. **Greater charge on the cation**: A higher charge on the cation increases its ability to polarize the anion.

Now, let's analyze the given compounds:

1. **FeCl2**: The cation is Fe²⁺ (charge +2).
2. **SnCl2**: The cation is Sn²⁺ (charge +2).
3. **AlCl3**: The cation is Al³⁺ (charge +3).
4. **MgCl2**: The cation is Mg²⁺ (charge +2).

Next, we will evaluate the charge on the cations:

- Fe²⁺: +2
- Sn²⁺: +2
- Al³⁺: +3
- Mg²⁺: +2

From the above analysis, we can see that AlCl3 has the highest charge on the cation (+3). According to Fajans' rule, a higher charge on the cation leads to greater covalent character.

Next, we should consider the size of the cations. Among the cations, Al³⁺ is the smallest due to its high charge density, which also contributes to its ability to polarize the anion (Cl⁻).

Thus, based on Fajans' rule, the compound that shows the maximum covalent character is **AlCl3**.

### Final Answer:
The compound that shows the maximum covalent character is **AlCl3**.