Carbon-13 NMR Chemical Shift Guide

Carbon-13 NMR helps identify carbon atoms by their chemical shift patterns. Carbon-13 is a naturally occurring NMR-active isotope of carbon, but it has a low natural abundance of 1.1%. Carbon-12 is much more common, but it has zero nuclear spin, so it is NMR inactive.

Carbon-13 gives a weaker sig...

Carbon-13 is an NMR-active nucleus with low natural abundance.  

Its magnetogyric ratio is smaller than that of protons, making carbon-13 resonance weaker than proton resonance.

Carbon-13 chemical shifts appear between 0 and 220 ppm, a much larger range than that seen in protons.

For this reason, non-equivalent carbons have ...