Preparation of the [Cr(H2O)2CN (en) NO]+ ion in solution by acid hydrolysis of [CrH2O(CN)2 (en) NO] including its ion exchange separation is described. The polarographic properties of [Cr(H2O)2CN (en) NO]+ as well as the kinetics of its acid hydrolysis were studied. Reactions of this complex with Hg(II) and Ag(I) were investigated and binuclear and trinuclear adducts were found to form. Linkage isomerization of the bridging cyanide in such adducts is deduced from their electrochemical properties. The spontaneous isomerization of the unstable isomer with the Cr-NC bond to the stable isomer with the Cr-CN bond was followed after its liberation by a competitive complexation of Hg(II) with excess iodide. The kinetics of decomposition of the adducts with Hg(II) was measured to examine the influence of H+ and Hg(II) concentrations.