# Homework Help: Turnbull's blue's formula

1. Apr 28, 2015

### mooncrater

1. The problem statement, all variables and given/known data
In my textbook it's written that turnbull's blue is:
$Fe_3^{II}[Fe^{III}(CN)_6]$

2. Relevant equations
none.

3. 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.

2. Apr 28, 2015