Class 12 NEET Chemistry Coordination Compounds

Fe

→

–––

C

−−−

––––––

O
Due to back bonding between metal-carbon bond length of C - O increase (B.O of M-C ↑ B.O of C - C ↓ B.L of C-O ↑) Higher is negative charge on metal, higher is back bonding (synergic effect) so bond length is higher so answer is [Fe(CO)4]2−