K#Hg in tetrahydrofuran stirring overnight under N2; the soln. siphoned off, the solvent removed in vac., the residue extd. with pentane, cooling to -80°C, the solvent siphoned off, the crystals washed with pentane, recrystn. from pentane and drying in vac.; elem. anal.;

melting in vac. under N2;