Abstract: | The 33S NMR signal of gaseous carbonyl sulfide (COS) was monitored as a function of density for the first time. An extrapolation to the zero‐density limit permitted the measurement of nuclear magnetic shielding of an isolated COS molecule. An improved 33S shielding scale was established taking the value of 817(12) ppm as the absolute shielding of COS. The new 33S shielding scale is certainly more accurate than any previous estimation and contains some reference standards, e.g. an isolated SF6 molecule, a saturated solution of (NH4)2SO4 in D2O, 2 M aqueous Cs2SO4 solution or liquid SF6, CS2 and SO2. The latter results can be applied for the easy estimation of sulfur shielding available from all the measurements of 33S NMR chemical shifts. Copyright © 2002 John Wiley & Sons, Ltd. |