The pair in which both the species have the same magnetic moment (spin only) is :
Solution
Species with same number of unpaired
electrons have equal magnetic moment.
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<table class="tg">
<thead>
<tr>
<th class="tg-amwm">Complex</th>
<th class="tg-amwm">Ligand</th>
<th class="tg-amwm">Ligand Type</th>
<th class="tg-amwm">Number of unpaired electrons</th>
</tr>
</thead>
<tbody>
<tr>
<td class="tg-baqh">[Mn(H<sub>2</sub>O)<sub>6</sub>]<sup>2+</sup></td>
<td class="tg-baqh">H<sub>2</sub>O</td>
<td class="tg-baqh">Weak Field Ligand</td>
<td class="tg-baqh">5</td>
</tr>
<tr>
<td class="tg-baqh">[Cr(H<sub>2</sub>O)]<sup>2+</sup></td>
<td class="tg-baqh">H<sub>2</sub>O</td>
<td class="tg-baqh">Weak Field Ligand</td>
<td class="tg-baqh">4</td>
</tr>
<tr>
<td class="tg-baqh">[CoCl<sub>4</sub>]<sup>2–</sup></td>
<td class="tg-baqh">Cl</td>
<td class="tg-baqh">Weak Field Ligand</td>
<td class="tg-baqh">3</td>
</tr>
<tr>
<td class="tg-baqh">[Fe(H<sub>2</sub>O)<sub>6</sub>]<sup>2+</sup></td>
<td class="tg-baqh">H<sub>2</sub>O</td>
<td class="tg-baqh">Weak Field Ligand</td>
<td class="tg-baqh">4</td>
</tr>
<tr>
<td class="tg-baqh">[Co(OH)<sub>4</sub>]<sup>2–</sup></td>
<td class="tg-baqh">OH</td>
<td class="tg-baqh">Weak Field Ligand</td>
<td class="tg-baqh">3</td>
</tr>
<tr>
<td class="tg-baqh">[Fe(NH<sub>3</sub>)<sub>6</sub>]<sup>2+</sup></td>
<td class="tg-baqh">NH<sub>3</sub></td>
<td class="tg-baqh">Weak Field Ligand</td>
<td class="tg-baqh">4</td>
</tr>
</tbody>
</table>
About this question
Subject: Chemistry · Chapter: Coordination Compounds · Topic: Ligands and Coordination Number
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