Question

Using MOT, compare $O_2^{+}$ and $O_2^{-}$ species and choose the incorrect option.

• A. $O_2^{+}$ have higher bond order than $O_2^{-}$ .
• B. $O_2^{-}$ is less stable
• C. $O_2^{+}$ is diamagnetic while $O_2^{-}$ is paramagnetic
• D. Both $O_2^{+}$ and $O_2^{-}$ are paramagnetic.

Answer 1

Answer: (C)

$O_2^{+}$and $O_2^{-}$both are paramagnetic as $O_2^{-}$has 1-unpaired electrons and $O_2^{+}$has one unpaired electron. Thus can be illustrated by MOT as
$O_2^{-}\to \sigma 1s^2{\sigma }^{\ast }1s^2\sigma 2s^2{\sigma }^{\ast }2s^2\sigma 2p_z^2\pi 2p_x^2\pi 2p_y^2{\pi }^{\ast }2p_x^2{\pi }^{\ast }2p_y^1$
$O_2^{-}\Rightarrow B\cdot O=3/2$
$O_2^{+}\to \sigma 1s^2{\sigma }^{\ast }1s^2\sigma 2s^2{\sigma }^{\ast }2s^2\sigma 2p_z^2\pi 2p_x^2\pi 2p_y^2{\pi }^{\ast }2p_x^1{\pi }^{\ast }2p_y^0$
$O_2^{+}\Rightarrow B.O=5/2$ $ Higher the B.O. higher is the stability.