Determination of the proton chemical shielding tensor in anhydrous α-oxalic acid by multiple pulse NMR

Abstract

Multiple pulse line-narrowing methods have been used to determine the proton chemical shielding tensors in a single crystal of anhydrous α-oxalic acid. The results indicate approximate axial symmetry of the chemical shift about the nominal hydrogen bond directions with the largest shielding occurring when the external field is parallel to the hydrogen bond.