Is the formula for Turnbull's blue Fe₃[Fe(CN)₆] or Fe₃[Fe(CN)₆]₂?

[mooncrater]

Homework Statement

In my textbook it's written that turnbull's blue is:
$Fe_3^{II}[Fe^{III}(CN)_6]$

Homework Equations

none.

The Attempt at a Solution

But Shouldn't it be twice of the complex compound instead of one...to balance the charge.
I googled it but found the formula of the complex, not of the whole compound.
Thanks.
Any help appreciable.

 

[Borek]

You are right that the formula in your textbook is wrong.

http://en.wikipedia.org/wiki/Prussian_blue