I've been taking an chemistry class online (for fun only) and one of the questions in the homework threw me a bit. Here's the wording:

"Draw the Lewis structure for a nitrogen atom attached to. two methyl groups ($\ce{CH3}$) and one oxygen atom."

OK, so I know that $\ce{NO}$ is a free radical due to the odd combined valence, i.e., the octet rule isn't satisfied. Will that carry over when the $\ce{NO}$ bonds with the two methyl groups?

Here's the sketch of what I did:

enter image description here

Lastly, what's the name of this compound? This is not part of the HW question; I'm just curious.


1 Answer 1

  • Name of the compund: Dimethyl nitroxide
  • Lewis structure:

enter image description here

  • The properly way to determine the Lewis structure, based on this example, is:

    1. Total valence electrons: $4\cdot2 + 5 + 6 + 1\cdot6 = 25$
    2. Total electrons needed for octets/doublets: $8\cdot4+2\cdot6 = 44$
    3. Total shared/bonding electrons: $44 - 25 = 19$ (In other words, there is only nine single bonds and one electron left.)
    4. Total electrons in lone pairs: $\text{Step 1} - \text{Step 3} = 25 - 19 = 6$ (In other words, the are only 3 pairs of lone electrons.)
  • Furhter information on how to draw Lewis structures, please follow the link

  • Further information of related Lewis structures and how this knowledge is applied on real top science, I recommend seeing this reference: Moreira, G.; Charles, L.; Major, M.; Vacandio, F.; Guillaneuf, Y.; Lefay, C. and Gigmes, D. Beilstein J. Org. Chem., 2013, 9, 1589 - 1600.

  • 1
    $\begingroup$ In your first step, if you were just losing an electron then the middle structure would have a positive charge; but you've lost a hydrogen too - you need to factor that in. $\endgroup$
    – ron
    May 22, 2015 at 2:18
  • $\begingroup$ I agree with @ron, but I also see, that the image is directly taken from the Beilstein, who does make the mistake in the first place. || I personally would like it more, if you would write out the reference with names: Beilstein J. Org. Chem., 2013, 9, 1589–1600. $\endgroup$ May 22, 2015 at 2:48

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