Abstract
New measurements of the nuclear magnetic resonance(NMR) of perchloric acidsolutions furnish results of higher accuracy (about 0.002 ppm in the chemical shift) between 0° and 65°C. Discrepancies in the degrees of dissociation derived from older NMR data and Raman intensities are ascribed to short‐comings in the earlier interpretation. Extension of the measurements to deuterium solutions furnishes information to be used in the discussion of the molecular state of the acid and of the hydrogen ion.