Nuclear Magnetic Shielding in F2

Abstract

The 19F chemical shift between gaseous F2 and SiF4 has been measured to be − 596.0 ± 0.2 ppm at 30°C. With a recently established absolute shielding scale for 19F this value yields an absolute shielding in F2 of − 232.6 ppm. Combination of this with the measured spin–rotation constant leads to a separate determination of experimental values for σFd and σFp, with arbitrary choice of gauge origin, which are then compared with available theory. An estimate of the vibrational effects is given.