wiz-icon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

Among the following metal carbonyls, the CO bond order is lowest in

A
[Mn(CO)6]+
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
[Fe(CO)5]
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
[Cr(CO)6]
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
[V(CO)6]
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
Open in App
Solution

The correct option is D [V(CO)6]
The overlap of a lone pair on the C atom with the empty hybrid metal orbital forms a metal-to-carbon σ-bond. The transition metal atom in a metal carbonyl fills the non-bonding d-orbitals which are proper symmetry to overlap with the anti-bonding orbitals of CO. The electronic charge is transferred from the filled non-bonding orbitals of the metals to π-orbitals of the ligand CO. This reduces the bond order of CO. The π back-bonding strengthens the M-C bond order and weakens the C-O bond order.
CO is a strong ligand, it causes pairing of electrons.
Mn+:(z=25)
[Ar]3d54s1[Ar]3d64s0
Three lone pairs are available for back-bonding with vacant orbital of C in CO.
Fe0:(z=26)
[Ar]3d64s2[Ar]3d8
Four lone pairs are available for back-bonding with vacant orbotal of C in CO.
Cr0:(z=24)
[Ar]3d54s1[Ar]3d64s0
Three loan pairs are available for back-bonding with vacant orbital of C in CO.
V:(z=23)
[Ar]3d44s2[Ar]3d64s0
Three lone pairs are available for back-bonding with vacant orbital of C in CO.
Minimum back-bonding is possible in [V(CO)6]1, so the M-C bond order is the lowest.

flag
Suggest Corrections
thumbs-up
0
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Hybridization
CHEMISTRY
Watch in App
Join BYJU'S Learning Program
CrossIcon