Carbon-13 NMR Spectroscopy
Almost all carbon atoms are carbon-12 with just a small proportion being Carbon-13.
Carbon-13 has an odd number of nucleons (13) resulting in a residual magnetic spin.
- is a scale that compares the frequency of an NMR absorption
- with the frequency of the reference peak of TMS at 0ppm
Chemical shifts indicate the chemical environments of the carbon atoms present. The presence of an electronegative atom causes a significant chemical shift.