The [RuNO(Thio)4Cl]Cl2 compound (where Thio is thiocarbamide) was synthesized by reacting nitrozochloro complexes of Ru with thiocarbamide. Its structure and properties in solutions were studied by IR, EAS, EPR, Ph-metric, and electrical conductivity methods. The complex was found to have octahedral structure, with the chlorine atom in the trans-position relative to the nitrozo group, and four Thio groups coordinated through the sulfur atom and lying in the equatorial plane. This compound is labile in solutions. The mechanism and rate constants of the first hydrolysis stage were determined at 25, 50, and 75°C, and the enthalpy of the reaction was estimated. With a Thio excess, the nitrozo group is replaced to form the Ru(III) and Ru(II) thiocarbamide complexes.