Interestingly enough, if you look at protons C at the averaged #"1.200 ppm"#, you would also see that that doublet has the same #J# value (ideally that doublet should have both peaks at identical intensities too, but the shimming was not perfect, so they are a bit off). This distance is the numerical equivalent of the coupling constant #J# in #"Hz"#. It is not visible in this zoom, but the distance between each peak is roughly identical. What is shown here for proton A is that #"4.008 ppm"# is the average chemical shift of the 1-4-6-4-1 pattern (according to Pascal's triangle) from the rightmost peak to the leftmost peak, and the entire signal there has multiple peaks. ![]() Matching it up with other nearly-identical coupling constants elsewhere in the spectrum usually tells you which protons are near which others. The coupling constant #J# is pretty much the peak-to-peak distance, usually reported in #"Hz"#.
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