Which statements about Prussian blue, Fe4[Fe(CN)6]3, are correct? One or more options may be correct.

The same blue compound results from Fe^2+ and [Fe(CN)6]^3- (electron transfer takes place).

Iron is present in the +3 and +2 states in the ratio 4:3.

It is formed when Fe^3+ reacts with [Fe(CN)6]^4-.

The hexacyanoferrate(II) unit in it is paramagnetic.

The same blue compound results from Fe^2+ and [Fe(CN)6]^3- (electron transfer takes place).

Iron is present in the +3 and +2 states in the ratio 4:3.

It is formed when Fe^3+ reacts with [Fe(CN)6]^4-.

JEE Advanced levelOne or more correct optionsDifficulty 3 of 3qa109

Which statements about Prussian blue, $Fe X_{4} [Fe (CN) X_{6}] X_{3}$ , are correct? One or more options may be correct.

AThe hexacyanoferrate(II) unit in it is paramagnetic.
BThe same blue compound results from $Fe X^{2 +}$ and $[Fe (CN) X_{6}] X^{3 -}$ (electron transfer takes place).
CIron is present in the $+ 3$ and $+ 2$ states in the ratio $4 : 3$ .
DIt is formed when $Fe X^{3 +}$ reacts with $[Fe (CN) X_{6}] X^{4 -}$ .

Charge balance:

4 (+ 3) = + 12

is balanced by

3 (- 4) = - 12

from

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

, so Fe is

+ 3

(4 atoms, outer) and

+ 2

(3 atoms, in the cyanide units). Turnbull's blue rearranges by electron transfer to the same compound. The

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

unit is low-spin

d^{6}

and diamagnetic. Correct: first three.