Question

EAN of $Fe[{\eta ^5}({C_2}{H_5})C{O_2}Cl]$is:
A.36
B.35
C.37
D.34

Answer 1

Hint: EAN stands for the Effective Atomic Number and it is the total number of the electrons surrounding the nucleus of a metal atom in a metal complex is known as the EAN. Thus the EAN for the metals in a complex can be calculated easily.

Complete step by step answer:
EAN consists of the metal atom’s electrons and the bonding electrons from the surrounding electron-donating atoms and molecules. It can be calculated by the following formula:
EAN = Atomic number of the metal + (Number of ligands x electrons donated by each ligand) - positive oxidation state of the metal.

Another way to depict this formula generally is:
EAN $ = Z - x + 2nL$

Where Z= Atomic number of the metal in the complex.
x = Oxidation state of the metal in complex.
n= Number of the ligands.
L = Number of coordinate bonds formed by ligand.
In order to calculate the EAN of the of $Fe[{\eta ^5}({C_2}{H_5})C{O_2}Cl]$the following formula can be used:
EAN = Atomic number of the metal + (Number of ligands x electrons donated by each ligand) - positive oxidation state of the metal.
Thus EAN$ = 26 + (5 \times 2) = 0$
EAN$ = 26 + 10 = 0$
EAN $ = 36$

So, the correct answer is Option A.

Note: The EAN helps to understand why the electrons away from the nucleus have weaker control of the nucleus on them than the one which is in close proximity of the nucleus. The other properties can also be calculated through their simplified properties.