Degree of Unsaturation aka Index of Hydrogen Deficiency

Degrees of unsaturation index of hydrogen deficiency videoDegree of unsaturation is typically covered at the start of your organic chemistry course when you learn how to identify constitutional isomers. Yet it amazes me how many advanced orgo students still don’t understand or know this concept at the Orgo 2 level.

This concept is CRITICAL for finding isomers, identifying key structures during spectroscopy, and identifying the unknown in a complex reaction roadmap when only a formula is given.

What’s more confusing is the way this information is taught. A bunch of letters and numbers to calculate that appear to make little sense overall. This video will show you how to break up the complex ‘Degree of Unsaturation’ formula into very simple and easy to understand components.

You will hear this referred to as:

  • DOU = Degrees of Unsaturation
  • IHD = Index of Hydrogen Deficiency
  • DBE = Double Bond Equivalents

(Click HERE to watch this video on YouTube. Transcription coming soon)


  1. Eston C Clare says:

    I looked over the twice. I think there is a discrepancy in what you say while explaining Nitrogen (need to add a hydrogen) to your summary in your closing statements where you say that you should subtract a hydrogen for the existence of a Nitrogen. Can you clarify? It could very well be my misunderstanding. Awaiting your response. Otherwise, excellent video and logic.

    • Leah4sci says:

      Eston: BECAUSE you need to add 1 H for every Nitrogen your count will be too high and so you must SUBTRACT an H from the total number to compensate for the added N

  2. Schedule a bootcamp during the week for those who work weekend nights.

    • Unfortunately no matter what I schedule I won’t be able to fit everyone’s needs. That’s why every bootcamp is recorded with the ability for students to experience it at any time after the fact

I'd love to hear from you - Leave a comment below