NH3 in water addn. of dild. HCl to an aq. soln. of Na2WO4*2H2O; ppt. was isolated and dried; to the 'hydrated WO3' ammonia was added, the mixt. was stirred for 1 5. h, H2S was bubbled through the soln.; the mixt. was allowed to stand for 4 d;; ppt. was filtered;;

catalyst: 2-mercaptoethanol in water under Ar; tungstic acid and mercaptoethanol were dissolved in ammonia buffer at 70°C; Li2S was suspended separately in ammonia buffer; solutions combined after 30 min at 70°C; stirred at 70°C for 48 h; filtration of the hot solution through a Celite pad; filtrate left at -18°C for 2 days; filtration; washed with 2-propanol and ether; dried in vacuo; elem. anal.;

in water H2S passed through suspn. of H2WO4 in aq. NH4OH at 60 ° C for 30min, filtered, filtrate reheated to 60 ° C, H2S passed for 2 h, concd. NH4OH added, H2S passed for 5 h; mixt. stored in refregerator overnight, filtered, washed with EtOH, ether dried;

in water aq. soln. of NH3 added to H2WO4, satd. by slow addn. of H2S for 20 min at room temp., filtered, filtrate heated to 60°C with stirring andflow H2S for 7 h, purged with N2, cooled; filtered, dried under vac.; elem. anal.;

NH3 in ammonia; water aq. ammonia=NH3; stirring of WO3 in aq. NH3 for 18 h, saturation with H2S, 30-45 min; filtn., addn. of EtOH, crystn., washing with EtOH;

in ammonium hydroxide (NH4)10W12O41*14H2O dissolved in aq. soln. of NH3; kept for 4 h under H2S bubbling at 333 K; cooled and maintained at 273 K overnight; filtered; rinsed (acetone); dried (vac.);

in ammonia passing H2S into H2WO4 soln. for 4-5 h, filtration, pptn. in closed vessel for 8 d; washing with H2S-water, then with alc. and ether, drying in vac. over P2O5;

hydrogen byproducts: H2S; 7 h glowing in H-steam;

byproducts: H2O; heating;

at 400°C;