Talk:Phosphorus-31 nuclear magnetic resonance
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ppm direction convention
[edit]In 1975, the IUPAC made recommendations for nuclei other than protons[1] that specified the direction of the ppm scale. Due to this, reports pre ~1975 contain data of the opposite sign. E.g. -100 ppm before, and 100 ppm now.
I think it is worth mentioning this change on the Phosphorus-31 NMR page, as it is useful for anyone comparing with old literature.