Hnmr

[munecaDDS]

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how do you know which hydrogens are most down field is it the ones closer to a negative atom like Oxygen for example? An i know my book says more down field the more deshielded but what does that actually mean ?

 

[Pandawanda]

hello,

if H's are attached to a C that is attached to an electonegative element (like F or Cl), then think of it as the F pulling away the electrons from the C and H..making the H more deshielded, therefore downfield (shift left) from the inital peak (the highest one to the right).

if there are no electroneg elements, then the C and H are shielded by the electrons that revolve around it., therefore shifted upfield = shielded = shift right..

poorly worded but u get it.