Question

What is the EAN of nickel in $Ni{(CO)}_4$ ?

• A. 34
• B. 35
• C. 32
• D. 36

Answer 1

Answer: (D)

EAN = Ac. no. of central metal atom oxidation state of central metal atom + electrons gained from ligands
Atomic no. of $Ni=28$ Oxidation state of $Ni$ in $[Ni{(CO)}_4]=0$
( $\because$ Oxidation state of metal in carbonyl is zero)
Electrons gained from ligands $=2\times 4=8$
( $\because$ One ligand donates two electrons to metal atom.)
$\therefore$ $EAN=28-0+8=36$