Question

Which of the following molecule follows EAN rule?

• A. $Fe(CO{)}_5$
• B. $Ni(CO{)}_4$
• C. $K_4\left[Fe\right(CN{)}_6]$
• D. All follow the EAN rule

Answer 1

Answer: (D)

All follow the EAN rule

The effective atomic number value of complexes is as follows:

1. Fe in $Fe(CO{)}_5=26+10=36$ (10 electrons from 5 carbonyl groups).
2. Ni in $Ni(CO{)}_4=28+8=36$ (8 electrons from 4 carbonyl groups).
   
3. Fe in $K_4\left[Fe\right(CN{)}_6]=26-2+12=36$ (12 electrons from 6 cyanide groups).

Hence, all the complexes follow EAN rule.