Prussian blue, Fe4[Fe(CN)6]3, is formed when Fe^3+ reacts with K4[Fe(CN)6]. Which description is correct?

The four iron atoms outside the cyanide cages are Fe^3+ (N-bonded) and the three inside are Fe^2+ (C-bonded)

The three iron atoms inside the cages are Fe^3+ and the four outside are Fe^2+

The four iron atoms outside the cyanide cages are Fe^3+ (N-bonded) and the three inside are Fe^2+ (C-bonded)

The four Fe^3+ are C-bonded and the three Fe^2+ are N-bonded

JEE Main levelSingle correct optionDifficulty 2 of 3qc073

Prussian blue, $Fe X_{4} [Fe (CN) X_{6}] X_{3}$ , is formed when $Fe X^{3 +}$ reacts with $K X_{4} [Fe (CN) X_{6}]$ . Which description is correct?

AAll seven iron atoms are $Fe X^{2 +}$
BThe three iron atoms inside the cages are $Fe X^{3 +}$ and the four outside are $Fe X^{2 +}$
CThe four iron atoms outside the cyanide cages are $Fe X^{3 +}$ (N-bonded) and the three inside are $Fe X^{2 +}$ (C-bonded)
DThe four $Fe X^{3 +}$ are C-bonded and the three $Fe X^{2 +}$ are N-bonded

[Fe (CN) X_{6}] X^{4 -}

the iron is Fe(II) bonded to carbon. The extra

Fe X^{3 +}

ions bind to the nitrogen ends of the cyanides, so the formula contains 4 Fe(III) and 3 Fe(II). Charge check:

4 (+ 3) + 3 (- 4) = 0