G’day Dave; You can make gold chloride (AuCl4) by dissolving pure
(fine) gold in aqua regia, which is a mixture of one part by volume of
concentrated nitric acid and three parts of conc hydrochloric acid.
The nitric acid acts as a kind of catalyst in the reaction. You
should carry out the reaction in a well ventilated place, in a glass
vessel, and be careful not to breathe any of the fumes as they chew
lungs a bit. You may have to warm the mixture, but even so, the
reaction may take a while to complete, but you may find it goes more
quickly using gold filings. If you are thinking of using it to
make gold cyanide - DON’T!! the acid will liberate hydrogen cyanide
gas - which they use to kill criminals in America. There is a simpler
way to make gold cyanide.
It would probably be simpler to buy some gold chloride; perhaps one
of the larger jewellery suppliers would have some available, or
failing that a laboratory chemicals supplier - but gor blimey, guv; it
won’t 'arf cost yer!
John Burgess; @John_Burgess2 of Mapua Nelson NZ