Write IUPAC name of `Na_3 [ Co(NO_2)_6]`

Explanation

To write the IUPAC name of the coordination compound `Na3[Co(NO2)6]`, we will follow these steps:

### Step 1: Identify the Components
The compound consists of sodium ions (Na⁺) and a coordination complex `[Co(NO2)6]`. Here, Co is cobalt and NO2 is the nitrite ligand.

### Step 2: Determine the Charge of the Coordination Complex
The overall charge of the compound is neutral, and since there are three sodium ions (each with a +1 charge), the charge of the coordination complex must be -3 to balance it out.

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