H NMR help (1 Viewer)

[yepImhere]

What does chemical shift mean in H NMR and what do I need to memorise about it?

 

[Unovan]

What does chemical shift mean in H NMR and what do I need to memorise about it?

tetramethysilate (TMS) is the standard at 0 ppm
Chemical shift describes how shielded the nucleus is from the magnetic resonance of the nmr compared to TMS
So in a regular C-C bond the protons (H1) are very well shielded because there isn't much electronegativity difference whereas in bonds like a C=C or C=O bond there is a higher electronegativity difference so the proton is less shielded and thus the chemical shift is higher