IUPAC name of `[Fe(CN)_(6)]^(3-)` ion is

Options

A. hexacyanoferrate (II) ion
B. hexacyanoferrate (III) ion
C. hexacyanide iron (III) ion
D. iron (III) hexacyanide ion

Explanation

To determine the IUPAC name of the complex ion `[Fe(CN)_(6)]^(3-)`, we will follow the systematic rules for naming coordination compounds. Here’s a step-by-step breakdown of the process:

### Step 1: Identify the components of the complex ion
The complex ion consists of:
- A central metal ion: Iron (Fe)
- Ligands: Cyanide (CN)

### Step 2: Determine the oxidation state of the central metal ion
Let the oxidation state of iron be \( x \). The charge of the cyanide ligand (CN) is -1, and since there are 6 cyanide ligands, the total contribution from the ligands is \( -1 \times 6 = -6 \).

The overall charge of the complex ion is -3. Therefore, 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: Name the ligands
Since there are 6 cyanide ligands, we use the prefix "hexa-" to indicate the number of ligands. The name of the ligand "cyanide" is used in its neutral form, which is "cyano".

Thus, the name for the ligands is "hexacyano".

### Step 4: Name the central metal ion
The central metal ion is iron (Fe). Since the oxidation state is +3, in the context of an anionic complex, we change the suffix of iron to "ferrate". Therefore, we will refer to it as "ferrate(III)" to indicate the +3 oxidation state.

### Step 5: Combine the names
Now we combine the names of the ligands and the metal ion. The complete name of the complex ion is:
**Hexacyanoferrate(III)**

### Final Answer
The IUPAC name of the complex ion `[Fe(CN)_(6)]^(3-)` is **Hexacyanoferrate(III)**.

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