Chemists have revealed that $1 \lambda^{2}, 2 \lambda^{2}$ -disilene $\left(\mathrm{Si}_{2}\right)$ is diamagnetic while disulfur $\left(\mathrm{S}_{2}\right)$ is paramagnetic $(\mathrm{S}=1)$. Draw the MO diagram (valence shell only), determine the bond order for those two molecules and conjecture which element has higher $3 \mathrm{~s}-3 \mathrm{p}$ energy gap. (Note that $\sigma_{\mathrm{g} 3 \mathrm{pz}}$ is lower-lying than $\pi_{\mathrm{u} 3 \mathrm{p}}$ in $\mathrm{S}_{2} .$ )

It seems that the paramagnetic type is not very necessary - however, I couldn't come up with the correct MO diagram in either case.

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    $\begingroup$ use the easy to find diagrams for C2 and O2 as guides $\endgroup$
    – Andrew
    Commented Apr 8, 2021 at 20:24
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    $\begingroup$ Welcome to Chemistry! This appears to be a homework question, please share your thoughts and attempts towards the solution. In short: It would be a good idea to post whatever you have come up with so far. $\endgroup$ Commented Apr 8, 2021 at 20:56
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    $\begingroup$ Related: Why is diboron (B2) paramagnetic? $\endgroup$ Commented Apr 8, 2021 at 21:00
  • $\begingroup$ @Andrew Would the diagrams of $C_2$ and $O_2$ be sufficient to draw the original molecular orbital diagrams? Could you please elaborate more about what you mentioned, still can not figure out the relation between it and the given problem. $\endgroup$
    – Snowball
    Commented Apr 8, 2021 at 21:54
  • $\begingroup$ @Martin-マーチン How diboron's being paramagnetic such related to the stated problem?! The original question asks to draw the MO diagrams with valence shell only. I would be pleased if you could provide more insights about the proposed problem specifically. $\endgroup$
    – Snowball
    Commented Apr 8, 2021 at 21:55


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