Chloroauric acid white phosphorus

White phosphorus reduction. White phosphorus, and indeed sodium or potassium thiocyanate, are fast reducers. Chloroauric acid is boiled under reflux with white phosphorus (6) dissolved in diethylether. Boiling is continued until the solution turns from a brownish shade to red—this usually takes about 5 mm. This method produces gold particles m the smaller size range (2-12 nm) Accurate production of the particle size range is not easy, and, since the procedure is potentially highly dangerous, it is not commonly used... 

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