It is shown that adsorption of thiourea at a Ni-electrode in acetate soluti
ons is described by the Langmuir isotherm. A surface coverage near unity is
achieved at a thiourea concentration of 5 x 10(-5) mol/l. Starting from ne
arly the same concentration, the process of electroless nickel deposition c
eases to be initiated, evidently, due to covering the nickel's surface by t
hiourea.