According to molecular orbital theory, the number of unpaired electron(s) in${\mathrm{O}}_2^{2-}$ is_________

Electronic configuration of ${\mathrm{O}}_2^{2-}$ (according to MOT) is total electrons to be filled are 18${\mathrm{e}}^{-}$.

$\mathrm{\sigma }1{\mathrm{s}}^2{\mathrm{\sigma }}^{*}1{\mathrm{s}}^2\mathrm{\sigma }2{\mathrm{s}}^2{\mathrm{\sigma }}^{*}2{\mathrm{s}}^2\mathrm{\sigma }2{\mathrm{p}}_{\mathrm{z}}^2(\mathrm{\pi }2{\mathrm{p}}_{\mathrm{x}}^2=\mathrm{\pi }2{\mathrm{p}}_{\mathrm{y}}^2)({\mathrm{\pi }}^{*}2{\mathrm{p}}_{\mathrm{x}}^2={\mathrm{\pi }}^{*}2{\mathrm{p}}_{\mathrm{y}}^2)$ 

Total unpaired electrons in ${\mathrm{O}}_2^{2-}$ is zero.