The Kurnakov test is sometimes used to detect transplatin in samples of the drug cisplatin. In hot aqueous solution, the cis-compound reacts with aqueous thiourea (tu) to give a deeper yellow solution, from which yellow needles of [Pt(tu)]Cl chloride deposit on cooling. The trans-compound gives a colourless solution, from which snow-white needles of trans-[Pt(tu)(NH)]Cl deposit on cooling.