Which of the following species has a bond order other than 3?

Options

A. CO
B. `CN^(-)`
C. `NO^(+)`
D. `O_(2)^(+)`

Explanation

(d) The configuration of the given species can be written as
CO or `CN^(-)or NO^(+)(14e^(-))`
`=sigma1s^(2),overset(star)sigma1s^(2),sigma2s^(2),overset(star)sigma2s^(2),sigma2p_(z)^(2),pi2p_(x)^(2)=pi2p_(y)^(2)`
`O_(2)^(+)(8+8-1)=sigma1s^(2),overset(star)sigma1s^(2),sigma2s^(2),overset(star)sigma2s^(2),sigma2p_(x)^(2)`
`{pi2p^(2)y=pi2p_(z)^(2)overset(star)pi2p_(y)^(1)}`
Bond order `=(1)/(2)(N_(b)-N_(a))`
CO or `CN^(-) or NO^(+)=(1)/(2)(10-4)=3`
`O_(2)^(+)=(1)/(2)(10-5)=(5)/(2)=2.5`