HG-199 CHEMICAL SHIELDING TENSER OF THE MERCUROUS ION IN MERCUROUS NITRATE DIHYDRATE

Using single-crystal NMR, we have measured the full chemical shielding tensor of the Hg-2(2+) ion in mercurous nitrate dihydrate, the first tenser determination of a metallic species involved in a metal-metal b ond. The tenser is almost axially symmetric; its unique element is dir ected approximately along the long axis of the diaquomercurous ion, bu t it lies closer to the ligand metal axis than the metal-metal bond. T he shielding anisotropy of mercury is, as would be expected for a line ar mercury compound, quite large (3203 ppm).