Question

1. Which one of the mononuclear carbonyls does not obey EAN rule?
(a) Fe(CO),
(6) V(CO)
(c) Ni(CO)
(d) Cr(CO).​

Answer 1

Answer:

(b). V(CO)

Explanation:

The V(CO) mononuclear carbonyls does not obey EAN rule.

Hence the correct option is (b).

Answer 2

V(CO)₆ ​ does not obey the EAN rule. thus option (b) is the correct answer

EAN rule is also known as  the effective atomic number rule

Explanation:

The EAN  can be determined with this formula

EAN =Z-x+2nl

where :-

Z is the atomic number of the metal  in the complex

x is the oxidation state of the metal  in the complex

n is the number of ligands.

a) Fe(CO)₅

EAN=26−0+10=36. Thus, it follows the EAN rule.

b) V(CO)₆​

EAN=23−0+12=35. Thus, it does not follow the EAN rule.

c) Ni(CO)​₄

EAN= [ 28 - 0 + 2 × 4 × 1 ] = 28 + 8= 36. Thus, it follows EAN rule.

d) Cr (CO)​₆

EAN=24-0+12=36. Thus, it follows the EAN rule.

V(CO)₆ ​ does not obey the EAN rule. thus option (b) is the correct answer