In chemistry, a thioxanthate is an organosulfur compound with the formula RSCS2X. When X is an alkali metal, the thioxanthate is a salt. When X is a transition metal, the thioxanthate is a ligand, and when X is an organic group, the compounds are called thioxanthate esters. They are usually yellow colored compounds that often dissolve in organic solvents. They are used as precursors to some catalysts, froth flotation agents, and additives for lubricants.