The IUPAC name of the coordination compound `K_3[Fe(CN)_6]` is:

Options

A. tripotassium hexacyanoiron (II)
B. potassium hexaxyanoiron (II)
C. potassium hexacyanoferrate (III)
D. potassium hexacyanoferrate (II)

Explanation

To determine the IUPAC name of the coordination compound \( K_3[Fe(CN)_6] \), we can follow these steps:

### Step 1: Identify the Components of the Compound
The compound consists of potassium ions (\( K^+ \)) and a coordination complex \([Fe(CN)_6]^{3-}\). The cyanide ion (\( CN^- \)) acts as a ligand.

### Step 2: Determine the Oxidation State of Iron
Let the oxidation state of iron (\( Fe \)) be \( x \). The cyanide ion has a charge of \(-1\), and there are six cyanide ions in the complex. The total contribution from the cyanide ions is \( 6 \times (-1) = -6 \).

The total charge of the coordination complex is \(-3\) (since it is balanced by three potassium ions, each with a \( +1 \) charge, giving a total of \( +3 \)). Thus, we can set up the equation:

\[ x + (-6) = -3 \]

Solving for \( x \):

\[ x - 6 = -3 \\ x = +3 \]

So, the oxidation state of iron in this complex is \( +3 \).

### Step 3: Naming the Ligands
The ligand \( CN^- \) is named "cyano". Since there are six cyanide ligands, we use the prefix "hexa". Therefore, the name for the ligands is "hexacyano".

### Step 4: Naming the Central Metal Atom
The central metal atom is iron (\( Fe \)). Since the oxidation state of iron is \( +3 \), we use the name "ferrate" (as per IUPAC conventions, the suffix for metals in higher oxidation states is typically "-ate").

### Step 5: Combine the Names
Now, we combine the names of the cation and the anion. The cation is potassium, and the anion is "hexacyanoferrate(III)" (the oxidation state is indicated in Roman numerals).

Thus, the full IUPAC name of the coordination compound \( K_3[Fe(CN)_6] \) is:

**Potassium hexacyanoferrate(III)**

### Final Answer
The IUPAC name of the coordination compound \( K_3[Fe(CN)_6] \) is **Potassium hexacyanoferrate(III)**.

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