Which of the following species is not paramagnetic ?

Options

A. CO
B. `O_2`
C. `B_2`
D. NO

Answer

A

Explanation

CO
No of electron in CO= 6+8=14
`COto sigma1S^2, sigma^(**)1S^2, sigma2S^2, sigma^(**) 2S2^,`
`[pi2P_x^(2)=pi2P_y^(2)]sigma2P_z^(2)`
All electrons are paired so diamagnetic