Question

Which one of the following doesn’t follow the EAN rule?
A.$Fe{\left( {CO} \right)_5}$
B. $V{(CO)_6}$
C. ${K_4}[Fe\left( {CN{)_6}} \right]$
D. $M{n_2}{(CO)_{10}}$

Answer 1

EAN also known as the effective atomic number is the total number of electrons around the central metal ion present in a complex and calculated as the sum of the electrons on the metal ion and the number of electrons donated by the ligands.
Complete step by step answer: It can be calculated using the formula
EAN = $Z{\text{ }}-{\text{ }}X{\text{ }} + {\text{ }}Y$
Z= atomic number of the metal
X= number of electrons lost during the formation of the metal ion from its atom
Y= number of electrons donated by the ligands.
If the EAN value comes like the atomic number of a noble gas element then it follows the EAN rule otherwise it doesn’t follow the EAN rule.
EAN value of $Fe{\left( {CO} \right)_5}$ comes out to be 36 and which is equal to the atomic number of noble gas krypton hence it obeys EAN rule
EAN value of $V{(CO)_6}$ comes out to be 35 and which is not equal to any atomic number of noble gas element hence it doesn’t obey EAN rule
EAN value of ${K_4}[Fe\left( {CN{)_6}} \right]$ comes out to be 36 and which is equal to the atomic number of noble gas krypton hence it obeys EAN rule
EAN value of $M{n_2}{(CO)_{10}}$ comes out to be 36 and which is equal to the atomic number of noble gas krypton hence it obeys EAN rule.

Hence, the correct option is (B) $V{(CO)_6}$

Note: Make sure to confirm that If the EAN value comes like the atomic number of a noble gas element then it follows the EAN rule otherwise it doesn’t follow the EAN rule.