Cyano complex

Probably the most extensively applied masking agent is cyanide ion. In alkaline solution, cyanide forms strong cyano complexes with the following ions and masks their action toward EDTA Ag, Cd, Co(ll), Cu(ll), Fe(ll), Hg(ll), Ni, Pd(ll), Pt(ll), Tl(lll), and Zn. The alkaline earths, Mn(ll), Pb, and the rare earths are virtually unaffected hence, these latter ions may be titrated with EDTA with the former ions masked by cyanide. Iron(lll) is also masked by cyanide. However, as the hexacy-anoferrate(lll) ion oxidizes many indicators, ascorbic acid is added to form hexacyanoferrate(ll) ion. Moreover, since the addition of cyanide to an acidic solution results in the formation of deadly... 

A. G. Sharpe, The Chemistry of Cyano Complexes of the Transition Metals Academic Press, Inc., New York, 1976. 

Electroplating. Aluminum can be electroplated by the electrolytic reduction of cryoHte, which is trisodium aluminum hexafluoride [13775-53-6] Na AlE, containing alumina. Brass (see COPPERALLOYS) can be electroplated from aqueous cyanide solutions which contain cyano complexes of zinc(II) and copper(I). The soft CN stabilizes the copper as copper(I) and the two cyano complexes have comparable potentials. Without CN the potentials of aqueous zinc(II) and copper(I), as weU as those of zinc(II) and copper(II), are over one volt apart thus only the copper plates out. Careful control of concentration and pH also enables brass to be deposited from solutions of citrate and tartrate. The noble metals are often plated from solutions in which coordination compounds help provide fine, even deposits (see Electroplating). 

Use ofNHiOH in basic solution (especially for cyano complexes)... 

The most important low-spin octahedral complex of Mn is the dark-red cyano complex, [Mn(CN)6] , which is produced when air is bubbled through an aqueous solution of Mn and CN . [MnXs] (X = F, Cl) are also known the chloro ion, at least when combined with the cation [bipyH2] +, is notable as an example of a square pyramidal manganese complex. 

The case of C-coordinated oxazole, 21, was reported in organoiron chemistry (89JOM(372)287). Another example involves the interaction of the cyano complexes [M(CN)(Cp)(dppe)] (M = Fe, Ru) or [(rj -Cp)Fe(dppe)(CNH)]Br with gem-dicyanoepoxide to afford the oxazol-2-yl complexes with the C-coordination mode (96JCS(D)3231). 

Pesek, J.J. and Mason, W.R. (1979) Carbon-13 magnetic resonance spectra of diamagnetic cyano complexes. Inorganic Chemistry, 18, 924—928. 

Investigations of cyanides and cyano complexes of Cd and Hg have augmented tremendously since about 1990, after detection of inclusion compounds of Cd(CN)2. A thorough review on transition-metal cyanides especially emphasizes the chemistry of inclusion compounds of both the Hofmann type (frameworks dominated by planar Ni(CN)4 building blocks) and the cyanocad-mate type (frameworks with tetrahedral Cd(CN)4 units).87 The structures of these inclusion compounds, but also of cyanides themselves, often topologically resemble the structures of minerals this aspect ( mineralomimetic chemistry ) is dealt with in a simultaneous survey.88 A more generic review of framework structures, with a section on cyanide inclusion compounds, is also to be mentioned.90... 

A special situation is met in systems containing Cd or Hg combined with cyano-complexes of other elements. In these cases, the coordination sphere of Cd or Hg is fully or partly made up of the N-ends of cyano-groups C-bonded to another metal. 

See related METAL CYANIDES (AND CYANO COMPLEXES) See other SILVER COMPOUNDS... 

See entry metal cyanides (and cyano complexes) (reference 1)... 

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