No, closer to alchemy is the actual creation of gold from other elements with nuclear physics.
Was demonstrated quite a long time ago, but is not really practical to get meaningful quantities out of it.
(That is why I always prefered physics over chemistry - my chemistry book in school started with the story of the alchimists and concluded that they were bound to fail as gold cannot be created.
And in my physics book was just the formula to create gold)
> No, closer to alchemy is the actual creation of gold from other elements with nuclear physics.
The place where this happens is in the liquid mercury target of the Spallation Neutron Source at Oak Ridge. Here, high energy protons shatter (spall) mercury nuclei, producing fragments that can include gold. An uncommon isotope of mercury can also be converted to gold by neutron capture.
> is not really practical to get meaningful quantities out of it.
you can build the entire neutron spallation reactor out of materials much cheaper than gold, and you can get unlimited quantities; the only impracticality is that the humans are still really bad at building machinery
> not really practical to get meaningful quantities out of it.
It is quite practical. You just pour a big pile of hydrogen out, let gravity compress it until it starts fusing. Initially it will only create helium but near the end of the pile’s life you will get mountains of the other elements too.
Easy breasy. It just takes time and quite a bit of space and hydrogen. Much harder to scale it down of course. But think big and aim for a star as they say.
‘Natural’ fusion will only get you as far as iron. Supernovae may produce heavier elements, but the heaviest elements like gold are probably produced in neutron star collisions.
Supernova explosions are good enough to make gold (and most other heavier elements until plutonium) by neutron capture.
Fusion, as you say, produces quantities that diminish very quickly for the elements beyond iron (iron 56 has the greatest binding energy of any nucleus and the binding energy decreases slowly after it), so that the last element that is produced in non-negligible quantities by fusion is likely to be germanium.
Not really I think, as this is not transforming something else into gold, it just kind of lumps existing gold together (if I understood the article correctly).
We have a name for that kind of alchemy - nuclear fission/fusion.
Because gold is so inert (a noble metal) its counterintuitive to see it in other forms eg in solution. In that sense manipulating gold in other forms than its elemental form probably feels like alchemy in common parlance.
I know aqua regia is relatively normal but I still find it weird to think of gold being dissolved
Gold is difficult to oxidize, but once oxidized it has some of the biggest ions, which stay easily in solution if no reducing agent is present.
The ion Au(I) has about the same size as the ions of potassium (which are exceeded in size only by cesium, rubidium, thallium and radium).
The ion Au(III) has a more normal size, but it is still relatively big, similar to the trivalent ions of the rare earths.
The big size of the gold ions is one of the reasons why its combinations with small ions, like oxide and sulfide, are unstable, so you cannot find such minerals in nature.
On the other hand, the gold ions form stable compounds with bigger ions, like telluride. Therefore there are many minerals where gold is combined with tellurium (unlike silver and copper, which combine with the smaller sulfur).
Nevertheless, on Earth tellurium has an abundance almost as low as gold, even if tellurium is abundant in the Solar System. The reason is that tellurium is easily vaporized, so less of it has condensed when the Earth has formed and a good part from what has condensed initially has been lost later, when the Earth has been heated by many asteroid impacts during its early history.
While tellurium is rare because it went up, being lost as vapors, gold is rare because it went down and most of it is dissolved in the iron core of the Earth. Because both tellurium and gold are very rare at the surface of the Earth, the chances of them meeting together in amounts great enough to form a mineral are very low.
The result of this scarcity of tellurium on Earth is that most of the gold can be found as native gold and only a smaller fraction is found in compounds with tellurium. Had tellurium not been lost from Earth, the amount of native gold would have been very small, similarly with the much smaller amounts of native silver and copper that exist versus the amounts available in sulfide minerals.
Thanks for sharing this - excellent content. I've been out of the game for a long time now but isn't this just the case that Gold is too soft as an ion to mix well with stuff like oxides?
Cs(I) should be larger than Au(I) but it seems to form a comparatively stable oxide Cs2O. But yes Tellurium is also a nice soft element so AuTl have a good affinity for one another.
Was unaware of their chemistry, it doesn't even ring a bell tbh I wonder if I had ever encountered it before. I did enjoy studying the Post Transition Group Metals back in the day
Yes, as I have said, size is only one of the reasons of incompatibility with oxide ions.
As you say, gold has a much higher electronegativity than cesium and rubidium, i.e. not much lower than that of silicon, which makes it a "soft" ion, and that reduces the stability of any compound with oxide or hydroxide or fluoride ions. On the other hand, the incompatibility with the "softer" sulfide is mostly caused by the size ratio.
Well I'd argue getting threatened with a knife is relatively normal in London but that's off topic :)
Aqua regia is not particularly exotic as compared with all the fancy ways you can harm yourself or react things in Chemistry. You can probably prepare it at home using stuff that might be buyable over the counter.
Getting your hands on things like azides or Polonium 210 or having access to a nuclear reactor to do ad hoc fission/fusion is a lot less normal on that scale.
Additionally aqua regia has been known for quite a long time, from before we even knew about gases
Fwiw I forgot what the magic cleans everything mix was but I want to say it was H2SO4 and cif which we'd just squirt around in our fume hoods
For sure!
Cleaning solution, you’re thinking Piranha solution probably.
Aqua Regia definitely isn’t exotic (same as getting threatened with a knife), but also isn’t going to be nice to be around, and getting ‘cut’ is pretty easy if you don’t pay attention.
And either one are frowned upon at most dinner parties. At least the ones I’ve been to, but I try not to judge ;)
Obviously my comment was meant in jest, but I still think your typical 17th century alchemist would be quite convinced you've figured out Chrysopoeia if you showed them this process—even if it's just lumping trace amounts of gold together.
