To illustrate some of the concepts

To illustrate some of the concepts developed above, we will first concentrate on Carbon. The most abundant isotope 12C has no overall nuclear spin, having an equal number of protons and neutrons. The 13C isotope however does has spin 1/2, but is only 1% abundant. Carbon NMR spectra are characterised by the following;
* A chemical shift range of about 220 ppm, normally expressed relative to the 13C resonance of TMS.

* A natural linewidth of ca 1Hz, related to the values of the relaxation times T1 and T2.

* A Larmor frequency in the range of 20-100 MHz, for typical spectrometers.

* Typically about 5-20 mg of sample dissolved in 0.4 - 2 ml of solvent (normally CDCl3) are required, and a good spectrum would be obtained in 64 - 6400 scans.

Lets start by looking at a 13C spectrum of diethyl phthalate obtained by the FT technique;