Question
The common features among the species $$C{N^ - },CO$$ and $$N{O^ + }$$ are
A.
bond order three and isoelectronic
B.
bond order three and weak field ligands
C.
bond order two and$$\pi $$ —acceptors
D.
isoelectronic and weak field ligands
Answer :
bond order three and isoelectronic
Solution :
Number of electrons in each species are
$$C{N^ - } = 6 + 7 + 1 = 14,\,CO = 6 + 8 = 14\,$$ $$N{O^ + } = 7 + 8 - 1 = 14$$
Each of the species has $$14$$ electrons which are distributed in $$\,MOs$$ as below
$$\sigma 1{s^2},{\sigma ^*}1{s^2},\sigma 2{s^2},{\sigma ^*}2{s^2},$$ $$\left\{ {\pi 2p_y^2 = \pi 2p_z^2,{o^ - }2p_x^2} \right.$$
Bond order $$\, = \frac{{10 - 4}}{2} = 3$$