The IUPAC name of `K_4[Fe(CN)_6]` is

Options

A. Potassium hexacyanoiron (II)
B. Potassium hexacyanoferratte (III)
C. Potassium hexacyanoferrate (II)
D. Tripotassium hexacyanoiron (II)

Answer

To determine the IUPAC name of the compound \( K_4[Fe(CN)_6] \), we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Components**:
- The compound consists of potassium ions (K) and a complex ion \([Fe(CN)_6]^{4-}\).
- There are 4 potassium ions, which indicates that the overall charge of the complex ion is -4.

2. **Determine the Central Metal Atom**:
- The central metal atom in the complex is iron (Fe).

3. **Identify the Ligands**:
- The ligands in this complex are cyanide ions (CN). Each cyanide ion is a bidentate ligand, and there are 6 cyanide ions attached to the iron.

4. **Assign the Oxidation State**:
- In the complex ion \([Fe(CN)_6]^{4-}\), the cyanide ion (CN) has a charge of -1. Therefore, the total charge contributed by the 6 cyanide ions is -6.
- To balance the overall charge of -4, the oxidation state of iron (Fe) must be +2.

5. **Construct the Name**:
- The name of the complex ion is derived from the ligands and the central metal.
- The ligands are named first in alphabetical order, followed by the name of the metal with its oxidation state in Roman numerals.
- Since there are 6 cyanide ligands, we use the prefix "hexa" to indicate six.
- Therefore, the complex ion is named "hexacyanoferrate(II)".
- Since the compound contains potassium ions, we add "potassium" before the complex ion name.

6. **Final IUPAC Name**:
- Putting it all together, the IUPAC name of \( K_4[Fe(CN)_6] \) is "Potassium hexacyanoferrate(II)".

### Summary:
The IUPAC name of \( K_4[Fe(CN)_6] \) is **Potassium hexacyanoferrate(II)**.