Science & Fun | Home | Introduction into the ¹H NMR Spectroscopy

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A substance with four protons will show 4 NMR signals if all four protons have

chemical shifts, that is when they are

. That, however, is not the case for the four thiophene protons!
You should therefore ask yourself the following question:

When do resoncance signals occur at the same frequency?
Or to be more precise:
Under what circumstances are protons equivalent?
When you have your answer, check here!