Density:2.71 g/mL at 25℃(lit.)
Ammonium tetrathiotungstate is prepared by reaction of tungstate and ammonium sulfide solution.
Below are the steps：
1）Dissolve ammonium tungstate in ammonium hydroxide, the using amount of stronger ammonium water is: stronger ammonium water/ammonium metatungstate=1~2/1(ml/g);
2）Then the obtained solution react with ammonium sulfide solution, the mole ratio is S/W=4~6/1, the reaction temperature is under room temperature, reaction time is 0.5~3h, static crystallization time is 8~24h;
3）The last step is filter、rinsing、washing with absolute ethyl alcohol the crystallization, dry the product under room temperature, the ammonium tetrathiotungstate can be obtained.
Ammonium tetrathiotungstate prepared by this method is of high purity, among which the ammonium sulfide using amount is almost the same with the obtained ammonium tetrathiotungstate amount, react condition is alleviate, reaction time also decreases, so is the trash discharge amount. The product possess high yield and high purity. Omit the process of dealing with hydrogen sulfide.