Question

In the complex ${K_2}Fe[Fe{(CN)_6}]:$
A.Both $Fe$ atoms are in the same oxidation state
B.Both $Fe$ atoms are in the different oxidation state
C.In the coordination number of ion is $4$
D.The complex is a high spin complex

Answer 1

Hint: To find the nature of the spin and oxidation state it is important to observe the ligand bond. Apart we have to find the geometry of ${K_2}Fe[Fe{(CN)_6}]:$ as it is important to distinguish the ligand bonds, coordination and oxidation state.

Complete step by step answer:
Step $1$ :
First of all it is important to find the oxidation state of $Fe$ in the compound:
$
  0 = 2 + 2x - 6 \\
  2x = 4 \\
  x = \dfrac{4}{2} = 2 \\
 $
Therefore in the complex both the iron atoms have an oxidation state of $ + 2$.
Step $2$ :
As we can observe by the structure and the formula of the complex that it is surrounded by $6CN$ molecules. Now due to the bonding of $6CN$ molecules we can tell the coordination number will be $6$.
Step $3$ :
Next thing is to find the configuration of the ion in the compound.
$F{e^{2 + }}$ ions in the compound have $3{d^6}$ electronic configuration, which suggests low spin. Because of the lack of any unbonded electron. Furthermore because of the high oxidation state of the iron atom.
Step $4$ :
Therefore it has no unpaired electrons and with the magnetic moment of $0$ , and colourless.
So the correct option will be A.

Note:
Ligands are ions or neutral molecules that bond to a central metal atom or ion. Ligands act as Lewis bases (electron pair donors), and the central atom acts as a Lewis acid (electron pair acceptor). Ligands have at least one donor atom with an electron pair used to form covalent bonds with the central atom.