Dixylyl disulphide is a 1,2-bis(2,4-dimethylphenyl) thioether supplied as an impurity reference standard for monitoring impurities in the synthesis of hydrobromide vortioxetine. The compound has CAS 13616-83-6, molecular formula C16H18S2, and molecular weight 274.44 g/mol. It is provided in 1 g packs and should be stored under nitrogen at 4°C for short-term storage; in solvent, store at -80°C for up to 6 months or -20°C for up to 1 month.