Colloidal gold and nitric?

[SweetGold]

Is it possible for Gold to become colloidal after several days in nitric acid? How is colloidal gold actually made?

 

[Palladium]

Heres an interesting article. :arrow:

 

[eeTHr]

Heres an interesting article. :arrow:

In there it says that salt will cause the colloidal particles to aggregate into brown particles and settle.

 

[glondor]

Here is another article. It is actually a high school experiment with colloidal gold. It also states that salt will remove anions and allow gold to agglomerate.

http://nanoyou.eu/attachments/501_EXPERIMENT%20C1_Teacher%20document%2014-18.pdf

An investigation of the resulting chemistry should be done before attempting. HCL solutions will create hydrogen chloride gas when salt is added. Very bad.

http://msds.chem.ox.ac.uk/HY/hydrogen_chloride.html

 

[SweetGold]

Thanks for the information material. Very interesting! I also found an archived site that depicts the production of colloidal gold:
http://web.archive.org/web/20080615135923/http://mrsec.wisc.edu/Edetc/nanolab/gold/text.html

I love the red color. However none of these say anything about nitric acid, so it doesnt answer my first question.

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Is it possible for Gold to become colloidal after several days in nitric acid?

Im speaking of any type of gold or gold alloy that is placed into nitric. As we all know, gold is one of the very few metals that doesnt dissolve in nitric. However, Im wondering if, given sufficient time in the solution, the gold will eventually change too, namely into a colloidal state? I remember reading this somewhere on the net a while back and I cant find the source anymore. Back then it struck me as odd that gold would behave in such a way as I thought it would just stay suspended or precipitated in nitric, infinitely. But then again I dont know much about such processes, especially what colloids are concerned....

 

[Harold_V]

I expect that if you dilute gold enough with other metals, before parting, it's conceivable that you could create colloidal gold. I also expect that prolonged exposure to just nitric acid won't.

Harold

 

[butcher]

That makes a lot of sense to me, solutions of base metals, the gold seems to plate to metals in solution, and any organics just compound the troubles.