Talk:Phosphorus-31 nuclear magnetic resonance

ppm direction convention

In 1975, the IUPAC made recommendations for nuclei other than protons 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.

Seedybee123 (talk) 03:07, 22 January 2021 (UTC)

References