Cyanide, metal cations structures

This review analyses the vibrational spectra of complex cyanides and relates them to recently obtained structural data. In no structure is there a strong bond, and there may be no bond at all between the CN ligands and the metal cations. The H bonds are often very weak and when they are stronger, as in organic salts, they do not seem to influence the spectra. This invalidates Kharitonov s hypothesis which attempts to ex-... 

The deposition process of a metal is a special case of electrochemical kinetics. Details can be found in a recently published monography [1]. It is connected with the stepwise transfer of a cation from the electrolyte into the metal layer with its specific crystalline structure (cf. Fig. 1). The metal cation in the plating electrolyte exists as a complex MeL with ligands, either molecules of the solvent (e.g. H2O) or special complexing agents such as ammonia (NH3) or cyanide (CN ). After transport of this complex by diffusion or migration to the electrode (Step 1), it is adsorbed on the electrode surface accompanied by a partial loss of the ligand molecules and a partial reduction (Step 2, Eq. 1)... 

The high stability of the Au(I) cyanide complex reflects in an extremely small, actually vanishing, concentration of the metal ions. It is therefore reasonable to assume that the reduction or deposition of the metal at the cathode occurs from the complex ions, i.e., without formation of an intermediate simple ionic species. The direct reduction from the complex is generally considered as the most likely mechanism also for the deposition from cyanide complexes of other metal cations. In other words, the complex species in solution is the species undergoing electron transfer at the surface, and if any chemical modification of its structure takes place, this must be thought of as a surface reaction not involving complete decomposition of the complex itself and thus excluding the formation of the free cation. 

The preparation and reactions of metal cluster ions containing three or more different elements is an area with a paucity of results. The metal cyanides of Zn, Cd (258), Cu, and Ag (259) have been subjected to a LA-FT-ICR study and the Cu and Ag complex ions reacted with various reagents (2,256). The [M (CN) ]+ and [M (CN) +11 ions of copper, where n = 1-5, were calculated to be linear using the density functional method. The silver ions were assumed to have similar structures. The anions [M (CN) +1 of both copper and silver were unreactive to a variety of donor molecules but the cations M (CN) H + reacted with various donor molecules. In each case, where reactions took place, the maximum number of ligands added to the cation was three and this only occurred for the reactions of ammonia with [Cu2(CN)]+, [Cu3(CN)2]+, [Ag3(CN)2]+, and [ Ag4(CN)3]+. Most of the ions reacted sequentially with two molecules of the donor with the order of reactivity being Cu > Ag and NH3 > H2S > CO. 

Prussian blue — iron(III) hexacyanoferrate(II) is the archetype of sparingly soluble mixed valence polymeric metal hexacyanometalates with the formula Me Me(N) [Me c (CN)6] with (i), (N), and (C) indicating the position in the crystal lattice, where (i) means interstitial sites, (N) means metal coordinated to the nitrogen of the cyanides, and (C) means metal ions coordinated to the carbon of the cyanides. It is one of the oldest synthetically produced coordination compounds and was widely used as pigment in paints because of the intensive blue color. The compound has been studied extensively by electrochemical and other methods. The importance of Prussian blue in electrochemistry is related to the fact that it has two redox-active metal centers and that it has an open structure that allows small cations to... 

Cu(terpy)CN][N03]-H20 and [Cu(terpy)CN][C104] also exhibited anomalous magnetic properties 289). A structural analysis of the nitrate revealed a distorted five-coordinate geometry about the metal, with the fifth contact provided by the nitrogen atom of the cyanide of an adjacent cation 11). 

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