`[CoF_6]^(3-)` is a coordination complex ion.
How many unpaired electrons are there in the complex ?

Explanation

To determine the number of unpaired electrons in the coordination complex ion \([CoF_6]^{3-}\), we can follow these steps:

### Step 1: Determine the oxidation state of cobalt in the complex
The coordination complex is \([CoF_6]^{3-}\). Since fluorine (F) has a charge of -1 and there are 6 fluorine ligands, the total contribution from the ligands is:
\[ 6 \times (-1) = -6 \]
Let the oxidation state of cobalt be \(x\). The overall charge of the complex is -3, so we can set up the equation:
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