# Most negative and most positive value for proton chemical shifts

What are the most negative and the most positive values for proton chemical shifts recorded till present?

• I suspect the most positive values can be found in superacidic media such as $\ce{HF - SbF5}$, which contain extremely poorly solvated, essentially bare $\ce{H^+}$ ions. – Nicolau Saker Neto Aug 22 '14 at 14:08
• What are the values? – RBW Aug 22 '14 at 15:28
• It's been ages, but I stumbled on this article at random, showing a number of very closely related compounds with proton chemical shifts that vary from -58 ppm to +140 ppm! There are also some amusing carbon-13 shifts to be had. – Nicolau Saker Neto Feb 18 at 12:52