Dissolving Gold -> Smallest clusters method?

Greetings,

Could someone please help me learn, or point to some resource, concerning the chemistry of gold dissolutions in aqua regia and HCL?

Specifically, I am looking for information on how to obtain the smallest possible gold clusters in solution.

Thank you for sharing your knowledge and time. It is much appreciated.

Duncan

Replies

  • Kaustubh Katdare
    Kaustubh Katdare
    #-Link-Snipped-# ; over to you, sire.
  • Ramani Aswath
    Ramani Aswath
    Duncan Idaho
    Could someone please help me learn, or point to some resource, concerning the chemistry of gold dissolutions in aqua regia and HCL? Specifically, I am looking for information on how to obtain the smallest possible gold clusters in solution.
    What is the idea? Getting a colloidal gold solution? Gold nano particles? Red gold?
    If you can post some more info perhaps some one can come up with some pointers.

    #-Link-Snipped-#
  • Duncan Idaho
    Duncan Idaho
    Greetings Mr. Bioramani,

    It is a general question. I wish to know, in any form that is possible, what is the smallest average cluster size for gold one can achieve?

    Thank you for sharing your time and knowledge.

    Sincerely,


    Antoine

    p.s.: Here is the procedure which created much contention around chemists:

    (1) 50 mg gold (99.99% pure) were dispersed in 200 ml aqua regia to provide clusters of gold atoms.

    (2) 60 ml concentrated hydrochloric acid were added to the dispersion and the mixture was brought to boil, and continued boiling until the volume was reduced to approximately 10-15 ml. 60 ml concentrated HCl were added, and the sample brought to boil and checked for evolution of NOCl fumes. The process was repeated until no further fumes evolved, thus indicating that the nitric acid had been removed and the gold had been converted completely to the gold chloride.

    (3) The volume of the dispersion was reduced by careful heating until the salt was just dry. "Just dry" as used herein means that all of the liquid had been boiled off, but the solid residue had not been "baked" or scorched.

    (4) The just dry salts were again dispersed in aqua regia and steps (2) and (3) were repeated. This treatment provides gold chloride clusters of greater than 11 atoms.

    (5) 150 ml 6M hydrochloric acid were added to the just dry salts and boiled again to evaporate off the liquid to just dry salts. This step was repeated four times. This

    procedure leads to a greater degree of sub-division to provide smaller clusters of gold chloride. At the end of this procedure an orangish-red salt of gold chloride is obtained. The salt will analyze as substantially pure Au2Cl6.

    (6) Sodium chloride is added in an amount whereby the sodium is present at a ratio 20 moles sodium per mole of gold. The solution is then diluted with deionized water to a volume of 400 ml. The presence of the aqueous sodium chloride provides the salt Na2Au2Cl8. The presence of water is essential to break apart the diatoms of gold.

    (7) The aqueous sodium chloride solution is very gently boiled to a just dry salt, and thereafter the salts were taken up alternatively in 200 ml deionized water and 300 ml 6M hydrochloric acid until no further change in color is evidenced. The 6M hydrochloric acid is used in the last treatment.

    (8) After the last treatment with 6M hydrochloric acid, and subsequent boildown, the just dry salt is diluted with 400 ml deionized water to provide a monoatomic gold salt solution of NaAuCl2'XH2O. The pH is approximately 1.0.

    (9) The pH is adjusted very slowly with dilute sodium hydroxide solution, while constantly stirring, until the pH of the solution remains constant at 7.0 for a period of more than twelve hours. This adjustment may take several days. Care must be taken not to exceed pH 7.0 during the neutralization.

    (10) After the pH is stabilized at pH 7.0, the solution is gently boiled down to 10 ml and 10 ml concentrated nitric acid is added to provide a sodium-gold nitrate. As is apparent, the nitrate is an oxidizer and removes the chloride. The product obtained should be white crystals. If a black or brown precipitate forms, this is an indication that there is still Na2Au2Cl8 present. If present, it is then necessary to restart the process at step (1).

    (11) If white crystals are obtained, the solution is boiled to obtain just dry crystals. It is important not to overheat, i.e., bake.

    (12) 5 ml concentrated nitric acid are added to the crystals and again boiled to where the solution goes to just dry. Again it is essential not to overheat or bake. Steps (11) and (12) provide a complete conversion of the product to a sodium-gold nitrate. No chlorides are present.

    (13) 10 ml deionized water are added and again boiled to just dry salts. This step is repeated once. This step eliminates any excess nitric acid which may be present.

    (14) Thereafter, the just dry material is diluted to 80 ml with deionized water. The solution will have a pH of approximately 1. This step causes the nitrate to dissociate to obtain NaAu in water with a small amount of HNO3 remaining .

    (15) The pH is adjusted very slowly with dilute sodium hydroxide to 7.0 + 0.2. This will eliminate all free acid, leaving only NaAu in water.

    (16) The NaAu hydrolyzes with the water and dissociates to form HAu. The product will be a white precipitate in water. The Au atoms have water at the surface which creates a voluminous cotton-like product.

    (17) The white precipitate is decanted off from any dark gray solids and filtered through a 0.45 micron cellulose nitrate filter paper. Any dark gray solids of sodium auride should be redissolved and again processed starting at step (1).

    (18) The filtered white precipitate on the filter paper is vacuum dried at 120C for two hours. The dry solid should be light grey in color which is HAuXH2O and is easily removed from the filter paper.

    (19) The monoatomic gold is placed in a porcelain ignition boat and annealed at 300C under an inert gas to remove hydrogen and to form a very chemically and thermally stable white gold monomer.

    (20) After cooling, the ignited white gold can be cleaned of remaining traces of sodium by digesting with dilute nitric acid for approximately one hour.

    (21) The insoluble white gold is filtered on 0.45 micron paper and vacuum dried at 120C for two hours. The white powder product obtained from the filtration and drying is pure G-ORME.

    The G-ORME made according to this invention will exhibit the special properties described in the "General Description" of this application, including catalytic activity, special magnetic properties, resistance to sintering at high temperatures, and resistance to aqua regia and cyanide attack.
  • Ramani Aswath
    Ramani Aswath
    Duplicate post. Erased.
  • Ramani Aswath
    Ramani Aswath
    Thanks for that. I did look at David Hudson's work and the Halexandria site on ORME white Gold. Looks as though this has do do with alchemy, a study far removed from my orbit.

    However, it is interesting to know a bit about far out work being done.

    #-Link-Snipped-#

    www.halexandria.org
  • Duncan Idaho
    Duncan Idaho
    Greetings Mr. Bioramani,

    I sincerely hope you will have the time to focus on the chemistry I posted above.

    However much lore there has been attached to this patent, the science being described is what I trying to understand. The science, the chemistry, the specific procedure is what I posted. I hope members of this forums are not discredited when they look at specific chemical procedures and those procedures are associated with lore and myths. The myths are entertaining of course, but the specific step by step patent chemical procedure is what I asked about here.

    Please, members of this forum, don't break my heart and show yourselves to be nothing more than the Spanish Inquisition in disguise!

    Sincerely,

    Antoine
  • Ramani Aswath
    Ramani Aswath
    I apologise if you got the wrong impression. CE is a very tolerant forum. Everything under the sun and some way beyond also gets actively discussed. There is nothing judgemental in the comments put up. Generally, if we have nothing meaningful to contribute we say so, which was the case in my post. It is no reflection on lores or myths. After all India probably has more of those than most countries.

    Coming back to the step by step procedure described, it seems too elaborate for the intended purpose.
    There is no recorded demonstration that the procedure produces mono molecular particles. Probably an X Ray diffraction pattern will reveal the nature of the clusters.
  • Duncan Idaho
    Duncan Idaho
    Dear BioRamani,

    Thank you for responding.

    Just to share upon your suggestion... Under x-ray diffraction the material analyzes as silica and aluminium. To actually get the gold to show out of the sample you need to follow the Gainsburg Russian arc spectroscopy (in argon chamber) and wait around 200 seconds. This is a standard reference book, and a standard procedure in Russia. Everything else will burn in the first seconds, then you'll get nothing for a long, long time, then each PGM will read in turn at around 200 seconds.

    Sincerely,

    Antoine
  • Dem274
    Dem274
    Did anybody find out if this holds a magnetic field at room temp, or even do a spectroscopy on this material. It would be interesting to see. Also it may have bio medical research potential. Also its not alchemy, its first year chemistry to make. However, how can it read aluminum and silica if is only AUCL. Impossible, how can there be a transmutation, with out neutron emission.

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