Thioacetamide

Thioacetamide is an organic compound (formula CH3CSNH2, that appears as a white crystal under standard conditions. It is soluble in water and ethanol, and has a melting point between 110 and 115°C. In laboratories, it can serve as a source of sulfur in the synthesis of organic compounds. It is stable at room temperature, but can produce hydrogen sulfide gas when heated, making it an ideal source, as opposed to storing toxic hydrogen sulfide as a gas in laboratories. Thioacetamide is carcinogen class 2B.

Uses in Qualitative analysis
When testing a solution for cations,  Thioacetamide becomes very useful. When put into a basic solution, this chemical can be heated to produce sulfide ions. Thioacetamide will decompose into Hydrogen Sulfide which will quickly react with the basic solution. This is favorable because it does not introduce any cations. So cations such as Copper, Cadmium, Mercury(II),  or other sulfide insolubles can be separated.