Chemical formula for in iron(III) hexacyanoferrate(II) is

Options

A. `Fe[Fe(CN)_(6)]`
B. `Fe_(2)[Fe(CN)_(6)]`
C. `Fe_(4)[Fe(CN_(6)]_(3)`
D. `Fe[Fe(CN_(6)]_(3)`

Explanation

To find the chemical formula for iron(III) hexacyanoferrate(II), we can follow these steps:

### Step-by-Step Solution:

1. **Identify the oxidation states**:
- Iron(III) indicates that iron has a +3 oxidation state, which can be represented as Fe³⁺.
- Hexacyanoferrate(II) indicates that the central iron (ferrate) has a +2 oxidation state, represented as Fe²⁺.

2. **Determine the cyanide ion**:
- The term "hexa" means six, so hexacyano refers to six cyanide ions (CN⁻). Therefore, we have 6 cyanide ions contributing a total charge of 6(-1) = -6.

3. **Construct the complex ion**:
- The complex ion formed will be [Fe(CN)₆]²⁻ because the total charge from the six cyanide ions is -6, and we need to balance it with the +2 from Fe²⁺. Thus, the overall charge of the complex ion is -4.

4. **Combine the iron ions**:
- Since we have Fe³⁺ (from iron(III)) and need to balance the overall charge, we need to combine the Fe³⁺ ions with the complex ion. The charge of the complex ion is -4, and we have one Fe³⁺ ion contributing +3. To balance the charges, we need one more Fe³⁺ ion, giving us a total of +6 from two Fe³⁺ ions.

5. **Write the final formula**:
- The final formula for the compound will be composed of two Fe³⁺ ions and one [Fe(CN)₆]²⁻ complex ion. This results in the formula:
\[ \text{Fe}_3[\text{Fe(CN)}_6] \]

### Final Chemical Formula:
The chemical formula for iron(III) hexacyanoferrate(II) is:
\[ \text{Fe}_3[\text{Fe(CN)}_6] \]