NMR is one of the strongest tools that can be used to determine the molecular structure of organic compounds. There are two common types of NMR that you need to know for the DAT:

  1. H NMR

  2. C NMR.

The main difference between H NMR and C NMR is that H NMR is used to determine the types and number of hydrogen atoms present in a molecule whereas C NMR is used to determine the type and number of carbon atoms in a molecule. Below, we will take a closer look at both.

H NMR

For H NMR, you are looking at the H's attached to the neighbouring C and follow the n+1 splitting rule for the peaks. For example, methanol will have two non-equivalent peaks for CH3 and OH, as shown below.

The methyl proton will be a duplet because it is next to one alcohol proton. According to the n+1 splitting rule, you will have CH3 peak = 1+1 = 2 or a duplet. Likewise, the alcohol proton will have a quartet because it has 3 methyl protons at the adjacent C. Therefore, it will have OH peak = 3+1 = 4 or a quartet.

C NMR

For C NMR, you don't look at the adjacent C like in H NMR, but you should look at the functional group attached to it. Using the same example with methanol, since there is only one C, there will be one peak, or a singlet, as shown below.

So you see that CH3OH only has 1 peak because there's only one C present in the molecule. Back to your question, for H NMR, the equivalent Hs will not be shown on the image; however, for C NMR, the equivalent Cs will not be shown on the image.

Still not understanding NMR Spectroscopy? For more information, we recommend reviewing Professor Dave's video on NMR Spectroscopy.

Did this answer your question?