Question

Consider the following complexes:
1. $Fe(CO{)}_s$
2. $Ni(CO{)}_4$
3. $K_4\left[Fe\right(CN{)}_6]$
4. $N{a}_3\left[Cu\right(SCN{)}_4]$
Which of the above complexes obey $EAN$ rule?

• A. $1$ and $2$ only
• B. $2,3$ and $4$ only
• C. $1,2,3$ and $4$
• D. None of these

Answer 1

The correct option is C $1,2,3$ and $4$

EAN rule:-

The total number of $e^{-}s$ linked with the central metal atom or ion in a complex plus the $e^{-}s$ donated by the ligand is known as Effective Atomic Number, i.e; $EAN$. It is the attainment of noble gas configuration.

$EAN=Z-x+2nL$

$Z$= atomic number of the metal in the complex ion.

$x$= oxidation state of the central metal atom.

$n$= no. of ligands.

$L$= no. of coordinate bond formed by the ligand.

EAN rule:-

The total number of $e^{-}s$ linked with the central metal atom or ion in a complex plus the $e^{-}s$ donated by the ligand is known as Effective Atomic Number, i.e; $EAN$. It is the attainment of noble gas configuration.

$EAN=Z-x+2nL$

$Z$= atomic number of the metal in the complex ion.

$x$= oxidation state of the central metal atom.

$n$= no. of ligands.

$L$= no. of the coordinate bond formed by the ligand.

$Fe\left(CO{)}_5\right(EAN)=26-0+2\times 5\times 1$

$\Rightarrow 26+10=36$.

$Ni\left(CO{)}_4\right(EAN)=28-0+2\times 4\times 1$

$\Rightarrow 28+8=36$.

$K_4\left[Fe\right(CN{)}_6]⟶[Fe(Cn{)}_6{]}^{4+}$

$EAN=26-\left(2\right)+2\times 6\times 1$

$\Rightarrow 24+12=36$.

$N{a}_3\left[Cu\right(SCN{)}_4\left]\right(EAN)=29-1+2\times 4\times 1$

$\Rightarrow 28+8=36$.

Hence, all of them are following $EAN$ Rule.