IUPAC name of `K_3Fe(CN)_6` is

Explanation

To determine the IUPAC name of the coordination compound \( K_3Fe(CN)_6 \), we can follow these steps:

### Step 1: Identify the components of the compound
The compound \( K_3Fe(CN)_6 \) consists of:
- Potassium ions (\( K^+ \))
- A central metal ion, which is iron (\( Fe \))
- Six cyanide ligands (\( CN^- \))

### Step 2: Determine the oxidation state of the central metal ion
To find the oxidation state of iron in this complex, we can set up the following equation based on the charges:
- Let the oxidation state of iron be \( x \).
- The total charge contributed by the six cyanide ligands is \( 6 \times (-1) = -6 \).
- The total charge of the compound must equal zero since it is neutral.

Thus, we have:
\[ x + (-6) + 3 = 0 \]
Where \( 3 \) is the contribution from the three potassium ions (\( 3 \times +1 \)).
Solving for \( x \):
\[ x - 6 + 3 = 0 \\ x - 3 = 0 \\ x = +3 \]
So, the oxidation state of iron is \( +3 \).

### Step 3: Naming the ligands
The ligand \( CN^- \) is called "cyano". Since there are six cyanide ligands, we use the prefix "hexa" to indicate the number of ligands. Therefore, we refer to it as "hexacyano".

### Step 4: Naming the central metal ion
The central metal ion is iron, and since its oxidation state is \( +3 \), we denote it as "ferrate(III)" in the name.

### Step 5: Combine the names
Putting it all together, the IUPAC name of the compound \( K_3Fe(CN)_6 \) is:
\[ \text{Potassium hexacyanoferrate(III)} \]

### Final Answer:
The IUPAC name of \( K_3Fe(CN)_6 \) is **Potassium hexacyanoferrate(III)**.

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