sodium hydroxide; tin(ll) chloride in ethanol; water soln. of SnCl2 added to soln. of NaOH in water, suspension of Hg-compd. in EtOH/H2O added to stirred mixt. during 1h, stirred at room temp. overnight, diluted with water; extd. (ether), dried (Na2SO4), filtered, evapd.; elem. anal.;