Reduction of Au(CN) sub 2 sup minus in aqueous solution. Formation of nonmetallic clusters and colloidal gold
- Hahn-Meitner-Institut Berlin GmbH (Germany, F.R.)
Au(CN){sub 2}{sup {minus}} is reduced by hydrated electrons and hydrogen atoms. Three primary reduction products, which are in protolytic equilibrium, are formed depending on pH: Au(CN){sub 2}{sup 2{minus}} + 2H{sup +} {l reversible} Au(CN){sub 2}H{sup {minus}} + H{sup +} {l reversible} Au(CN){sub 2}H{sub 2}. The absorption spectra of the three species, the pK values of their protolytic equilibria, and their rates of decay into Au{sup 0} + 2CN{sup {minus}} (or HCN) were measured by the method of pulse radiolysis. The absorption spectrum of the gold atom is also reported. The agglomeration of gold atoms yields intermediate clusters of nonmetallic gold and finally colloidal metal. Hydroxymethyl and 2,2-methylhydroxypropyl radicals can also reduce Au(CN){sub 2}{sup {minus}}, although the specific rates are low. Gold atoms have strong reducing properties, the standard potential of the system Au{sup +}/Au{sup 0} being -1.5 V. Various organic radicals are reduced by Au{sup 0}. It is proposed that these reductions do not occur as simple electron-transfer reactions but through hydrolysis of intermediate organo-gold compounds.
- OSTI ID:
- 6986080
- Journal Information:
- Journal of Physical Chemistry; (USA), Journal Name: Journal of Physical Chemistry; (USA) Vol. 93:18; ISSN JPCHA; ISSN 0022-3654
- Country of Publication:
- United States
- Language:
- English
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360600 -- Other Materials
360603* -- Materials-- Properties
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400400 -- Electrochemistry
AQUEOUS SOLUTIONS
CHEMICAL REACTIONS
CLUSTER MODEL
COLLOIDS
DATA
DATA ANALYSIS
DISPERSIONS
EXPERIMENTAL DATA
GOLD COMPOUNDS
INFORMATION
MATERIALS
MATHEMATICAL MODELS
MEASURING INSTRUMENTS
MEASURING METHODS
MIXTURES
NUCLEAR MODELS
NUMERICAL DATA
REDUCTION
SEMICONDUCTOR MATERIALS
SOLUTIONS
TRANSITION ELEMENT COMPOUNDS