The compound `K_(4)[Fe(CN)_(6)]` is called

Options

A. potassium ferrocyanide
B. potassium ferricyanide
C. potassium hexacyanoferrate (lll)
D. potassium hexacyanoferrate (II)

Answer

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

### Step 1: Identify the Components
The compound consists of potassium ions (K\(^+\)) and a complex ion \([Fe(CN)_6]^{4-}\). Here, \(Fe\) is the central metal ion and \(CN^-\) is the ligand.

### Step 2: Determine the Ligand Name
The ligand \(CN^-\) is called cyanide. Since there are six cyanide ligands, we use the prefix "hexa" to indicate the number of ligands. Therefore, the ligand name becomes "hexacyano".

### Step 3: Identify the Metal and Its Oxidation State
The metal in the complex is iron (Fe). To find the oxidation state of iron in this complex, we can set up an equation based on the charge of the complex ion:

Let the oxidation state of iron be \(x\).
The total charge contributed by the six cyanide ligands is \(6 \times (-1) = -6\).
The overall charge of the complex ion is \(-4\).

So, we can set up the equation:
\[ x + (-6) = -4 \]
Solving for \(x\):
\[ x - 6 = -4 \\ x = -4 + 6 \\ x = +2 \]
Thus, the oxidation state of iron in this complex is +2.

### Step 4: Combine the Names
Now we can combine the names of the ligands and the metal along with its oxidation state. The name of the complex ion is "hexacyanoferrate(II)" because the oxidation state of iron is +2.

### Step 5: Include the Cation
Since the compound is a salt, we also include the cation name, which is potassium. Therefore, the full name of the compound is "potassium hexacyanoferrate(II)".

### Final Answer
The compound \( K_4[Fe(CN)_6] \) is called **potassium hexacyanoferrate(II)**.

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