Which of the following diatomic species contains solely bonds with exactly zero bonds according to M — Chemical Bonding Chemistry Question

💡 Solution & Explanation

$C_2$ has 12 electrons. Its valence MOT configuration is $\sigma 2s^2, \sigma^* 2s^2, \pi 2p_x^2 = \pi 2p_y^2$. The last 4 bonding electrons exclusively occupy the $\pi$ bonding orbitals, resulting in a bond order of 2 that consists of two $\pi$ bonds and no $\sigma$ bonds.