If I were to guess what happened to the gold foil, I'd suggest it dissolves itself via a nitrosonium intermediate: 4NOCl + Au -> [NO][AuCl4] + 3NO [NO][AuCl4] + H2O -> HNO2 + H[AuCl4] 2HNO2 -> NO2 + NO + H2O (-> dissolves chloroauric acid to form the yellow droplets in your petri dish)
@@jpolowin0 Yep, nitrosonium salts tend to react vigorously with moisture from the air, that's why I suggested it. If the oxidant was in-situ formed chlorine like it is for aqua regia then I couldn't really explain the yellow liquid. H[AuCl4] is not THAT hygroscopic and all other products are gases.
As always, beautifully filmed and stunning reactions. The almost disappearing gold foil is easy to understand. Gold foil is extremely thin and such a large piece of foil is only a few milligrams of gold. If this reacts to something else and the resulting compound is compacted into a small volume, then nearly nothing is left. I think that the yellow liquid looking stuff, adhering to the glass is a concentrated solution of HAuCl4. The evaporating cold ONCl leads to condensation of some water. Due to hydrolysis, this leads to formation of a mix of HNO3, HCl, ONCl and water, which dissolves the gold. The presence of the chloride makes oxidation of gold much easier, because it then can form a stable complex AuCl4(-). After evaporation of all ONCl, a strongly acidic concentrated solution of HAuCl4 remains behind.
As I understand it, NOCl is not the reason why aqua regia dissolves noble metals. It is simply an intermediate in its decomposition. The oxidizing ability of HNO3 combined with the coordinating ability of Cl- itself suffices to oxidize gold.
@@BradSchmoralmost, afaik the nitrosyl chloride can decompose via homolytic cleavage forming a chlorine radical (in this case also callednascent chlorine = in statu nascendi, which means in the state of creation/birth)which serves to oxidize the gold
@@BradSchmor It just seems very unlikely knowing that the concentration of NOCl/NO+ is far lower than the nitrate concentration at any time, and knowing that reactions of nitric acid with metals usually occur very readily. Moreover, it is known that [NO][PtCl4] forms during the dissolution of Pt, and the nitrosyl salt is only decomposed by treating with excess HCl, forming NOCl. That would indicate to me that nitrosyl is not the most potent oxidant, but rather a byproduct of the reaction.
thank you for another wonderful video showing and explaining experiments that as a hobbyist I can not do is so useful to me. your video presentations are a work of art.
@ oh yeah I’m subscribed to him too. I like him a lot. I used to be a huge fan of Nile Red but now he barely makes anything anymore so I’ve moved on to channels like this 😆
NileRed doesn't do as much ultradangerous stuff (although in some older videos he used some pretty hellish stuff - like chromyl chloride), but I think his videos are very interesting in their own right, UA-cam is big enough for them all.
'Cool' stuff! :D Seriously, it's thrilling to see this exotic material up close. Thanks for making all of this happen. For removing the ice condensate, you might consider spraying alcohol on the tube instead of wiping it-just a thought. But who am I to give advice to the God of chemistry? :D"
The waxy yellow residue is likely polymerization of gold chloride complexes with by-products from the decomposition of NOCl. The exact nature of this residue could depend on moisture content, temperature, the stoichiometry of NOCl relative to gold purity, and even the degree of decomposition or sublimation of the NOCl.
Isn't it the free chlorine that actually attacks gold? HCl fails to dissolve gold on its own because it's not very oxidizing, while oxidizing compounds like chlorine bleach can dissolve it without any help from HNO3. A compound that readily decomposes to NO and Cl2 should be expected to oxidize gold to AuCl4-.
the key in dissolving noble metals is to have halides present, as they can coordinate to the cations in highly acidic/oxidizing conditions and sufficiently lower the electrode potential to allow it to react with weaker oxidants. Hence chlorine in HCl will also do the job. However, it is difficult to obtain high aqueous concentrations of chlorine, hence aqua regia uses HNO3 as the oxidant instead. Using the stability constant of the AuCl4- complex allows you to calculate that the electrode potential of Au in concentrated chloride medium is below that of HNO3
Amazing work as always!! I bet you could sidestep the condensation issues by having a camera submerged in room temperature water. then you could just dunk the thing and record away.. Maybe there's a probescope that can go underwater (and isn't the cost of a small motorcycle).
Does the reaction of nitrosyl chloride with gold proceed in the same observed manner in a nitrogen atmosphere? I propose atmospheric oxygen and water are playing a role. Here's my guess: In inert, anhydrous conditions, 1 gold reacts with 4 nitrosyl chloride to make 1 mol nitrosyl tetrachloroaurate (charges not easily drawn on UA-cam, so it's drawn with a • ... but the NO is NO+ and the AuCl4 is AuCl4 -) and 3 mol nitric oxide. Au + 4 NOCl --> AuCl4-•NO + 3 NO but you did in an open atmosphere, where more things happen: 1. The evolved NO reacts with atmospheric oxygen further to NOx (visible as the brown gas NO2) 2. Nitrosonium tetrachloroaurate reacts with water to hydrolyze... AuCl4•NO + H2O --> HAuCl4 + HNO2 (which then decomposes further). So I believe the residue you see is tetrachloroauric acid... and then some hydrate of it.
@BradSchmor Yep I had the same idea. HNO2 decomposition produces more H2O, and the yellow residue looks exactly like the aqueous chloroauric acid solutions I used to work with!
@@At0mix sort of - only 1/2 a mol of water is evolved from the nitrous acid decomposition for every one consumed during the hydrolysis - so the net is half of a mol water consumption. I believe that under strict conditions the observation of the nitrosonium tetrachloroaurate would be possible, although it might be subject to some sort of disproportionation reactions - rates unknown. These exotic nitrogen salts always fascinate me because some of them are so fleeting, unstable, explosive, etc. Occupying only a tiny fraction of time as we know it, but revealing so much about chemistry itself.
I think at the reaction surface, the solution rose above it's temperature due to the temp of the gold and table n such, and that's when the reaction was stronger. It seemed to have a hard time, especially the more you cooled it down.
It could be said that the description of these systems can be quite complicated. I think that these reactions are uncontrollable ("strong oxidizing environment"), so kinetic parameters rather than thermodynamic ones are decisive. There can be many more products. After exposure to air humidity, even more. In general, it can be said that in systems where chlorine radical is generated and there is an excess of chloride anions, gold dissolves to AuCl4-, perhaps also by various mechanisms of action of oxidants in the reagent. However, if AuCl4- is exposed to an excess of water and a deficiency of chloride anions, it can be hydrolyzed to AuCl3(OH)-. What's on the dish? Maybe? A mixture of many different complex anions Au3+ and cations NO+, H3O+, H9O4+... :) If such a mixture were processed in some traditional way in hydrochloric acid, we would get after crystallization ais one substance like something like H7O3+AuCl4- or H9O4+AuCl4... :)
Why do you need to use the nitrogen sprayer rather than, say, a dry ice/methanol bath (-78.4°C)? The Cl₂ would remain liquid, and the NO a gas; the NOCl would, I expect, crystallize out when its concentration exceeded its solubility in liquid Cl₂. The sprayer's an interesting gadget (I've never seen one before) but it looks like it's a bit fussy, and control over the reaction temperature would be poorer than with a bath.
WOW! Thank you for this exotic video and all your hard work on this! I am surprised myself at how slowly and unreactively NOCl reacts with Au. I had expected a much faster reaction. I can add something about the disappearance of gold, which will probably make me unpopular here because I can refer to experience and not to sources: Gold often does not behave as described in the textbook. Gold shows a certain memory awareness in reactions. It is not possible to dissolve and precipitate gold, dissolve and precipitate again (cyclically) without a deviation from the specialist literature occurring. What is also exciting (and I have learned from my experience) is that the finest gold (e.g. gold foil)/gold compounds are a fairly volatile metal at low temperatures. It likes to evaporate (sublimated). That is totally confusing. Because I had never reached temperatures above 1200°C. After working with gold & its chemical compounds, my chemical extractor was often slightly gold-plated on the inside. This was not visible. It was only when the viewing windows were cleaned from the inside that the gold in the sponge was visible. There is a video somewhere on YT where someone dissolves 100g of gold and tries to precipitate it. I think I remember that he only gets 97-98g of precipitate. The person who made the video is totally surprised at the loss! The person who made the video thought the 2-3g were still in solution. I am convinced that a large part has evaporated (sublimated). This is totally confusing. I am sure that I will make myself unpopular with this comment because I cannot provide any citations or reviews for this paradoxical phenomenon. It is based solely on my chemical experience.
@@hamaljay exactly, it would be hard in this small of a solution but it would be interesting to so see the chemical experiment that results in getting the gold back and seeing what the recovery rate is.
Hey chemical force, Great Video! I was wondering if halogen azides are really that unstable, I have read on wiki that iodine azide is relatively more stable than other halogen azides.
When you added the nitrosyl chloride to the acetylene it looked like you had an intitial reactions, but then it died, was that the reaction fo residual chemicals?
Smart man make danger water turn yellow,smart man make danger yellow water go red,t smart man make water set fire, smart man can make gold go bye bye bye 😂😂😂
If Nitrosyl chloride is readily hydrolysed by water why does the production of Nitrosyl chloride with HCL and HNO3 not decompose almost immediately from water present in the acid as well as the water produced when Nitrosyl chloride itself is made?
Chemists are like the elemental computer programmers , They understand the codes (reactions). Just don't make a typo in that line of work! The risks are far worse!
Always the best reactions with exotic reagents!
If I were to guess what happened to the gold foil, I'd suggest it dissolves itself via a nitrosonium intermediate:
4NOCl + Au -> [NO][AuCl4] + 3NO
[NO][AuCl4] + H2O -> HNO2 + H[AuCl4]
2HNO2 -> NO2 + NO + H2O (-> dissolves chloroauric acid to form the yellow droplets in your petri dish)
Sounds about right 👍
Where should the necessary water have come from?
@@experimental_chemistry The moisture in the air would probably do it.
@@jpolowin0 Yep, nitrosonium salts tend to react vigorously with moisture from the air, that's why I suggested it. If the oxidant was in-situ formed chlorine like it is for aqua regia then I couldn't really explain the yellow liquid. H[AuCl4] is not THAT hygroscopic and all other products are gases.
I want to like this but I don't understand enough to make a "reaction"! :D
Tremendous work.
🤑This is true! Thank you!🤑
😅@@ChemicalForce
As always, beautifully filmed and stunning reactions. The almost disappearing gold foil is easy to understand. Gold foil is extremely thin and such a large piece of foil is only a few milligrams of gold. If this reacts to something else and the resulting compound is compacted into a small volume, then nearly nothing is left. I think that the yellow liquid looking stuff, adhering to the glass is a concentrated solution of HAuCl4. The evaporating cold ONCl leads to condensation of some water. Due to hydrolysis, this leads to formation of a mix of HNO3, HCl, ONCl and water, which dissolves the gold. The presence of the chloride makes oxidation of gold much easier, because it then can form a stable complex AuCl4(-). After evaporation of all ONCl, a strongly acidic concentrated solution of HAuCl4 remains behind.
As I understand it, NOCl is not the reason why aqua regia dissolves noble metals. It is simply an intermediate in its decomposition. The oxidizing ability of HNO3 combined with the coordinating ability of Cl- itself suffices to oxidize gold.
In fact, a molten mixture of hydrate aluminum nitrate and aluminum chloride will also dissolve gold, without producing NOCl.
I believe the nitrosonium moeity is the principal oxidant for aqua regia's reaction with gold - at least to get it from the metal to Au (I).
@@BradSchmoralmost, afaik the nitrosyl chloride can decompose via homolytic cleavage forming a chlorine radical (in this case also callednascent chlorine = in statu nascendi, which means in the state of creation/birth)which serves to oxidize the gold
@@BradSchmor It just seems very unlikely knowing that the concentration of NOCl/NO+ is far lower than the nitrate concentration at any time, and knowing that reactions of nitric acid with metals usually occur very readily.
Moreover, it is known that [NO][PtCl4] forms during the dissolution of Pt, and the nitrosyl salt is only decomposed by treating with excess HCl, forming NOCl. That would indicate to me that nitrosyl is not the most potent oxidant, but rather a byproduct of the reaction.
Thermodynamically yes, but without NOCl the kinetics are against.
Fresh aqua regia reacts very slowly.
Vielen Dank für den lehrreichen Inhalt. Bitte weitermachen!
thank you for another wonderful video
showing and explaining experiments that as a hobbyist I can not do is so useful to me.
your video presentations are a work of art.
You should react Nitrosyl Chloride with Sodium Azide to produce Nitrosyl Azide!
That sounds like a very Ex&F chemical...
This is THE BEST chemistry channel on UA-cam, bar none. Nile Red has nothing on you 😂
Explosions & Fire is also very good, especially if you want a bit more humour.
@ oh yeah I’m subscribed to him too. I like him a lot. I used to be a huge fan of Nile Red but now he barely makes anything anymore so I’ve moved on to channels like this 😆
@@KomradZX1989 and what he does make is only very loosely chemistry anymore. He just buys expensive toys to make food.
NileRed doesn't do as much ultradangerous stuff (although in some older videos he used some pretty hellish stuff - like chromyl chloride), but I think his videos are very interesting in their own right, UA-cam is big enough for them all.
Red paved the road that the rest tread upon
But CF also laid those early stones and is still producing quality content regularly
Thats really cool. I like the chemical reactions with the other metals.
The shots of the gold foil disappearing are crazy👍
It is not dissapearing, it's just extremely thin.
The red of this compound is beautiful
Brilliant production mate
Congrats on 200k man!
Great video and chemistry!
Let’s dissolve gold, but…aqueous solutions are cringe.
*Vaporizes your acid*
Okay, then, gas-phase aqua regia. Better?
Some options:
-Liquid trihalide salts
-Copper(II) or Iron(III) chloride in polar aprotic organic solvents
-SOCl2 in polar aprotic organic solvents
-Molten hydrated aluminum nitrate and chloride mixture
Bravo sir, bravo.
'Cool' stuff! :D Seriously, it's thrilling to see this exotic material up close. Thanks for making all of this happen. For removing the ice condensate, you might consider spraying alcohol on the tube instead of wiping it-just a thought. But who am I to give advice to the God of chemistry? :D"
Borat meets chemistry. And I thought I was near the end of UA-cam. Thank you.
Amazing demonstration 👍👍👍
What happens if you try to dissolve gold in a mix of nitric acid and HF ? I think it’s worth try it.
i have no idea what I am watching, but it is pretty damn cool.
Great footages and great explanations! Thank you !
Great video as always thank you for sharing!
The waxy yellow residue is likely polymerization of gold chloride complexes with by-products from the decomposition of NOCl. The exact nature of this residue could depend on moisture content, temperature, the stoichiometry of NOCl relative to gold purity, and even the degree of decomposition or sublimation of the NOCl.
Isn't it the free chlorine that actually attacks gold? HCl fails to dissolve gold on its own because it's not very oxidizing, while oxidizing compounds like chlorine bleach can dissolve it without any help from HNO3. A compound that readily decomposes to NO and Cl2 should be expected to oxidize gold to AuCl4-.
the key in dissolving noble metals is to have halides present, as they can coordinate to the cations in highly acidic/oxidizing conditions and sufficiently lower the electrode potential to allow it to react with weaker oxidants. Hence chlorine in HCl will also do the job. However, it is difficult to obtain high aqueous concentrations of chlorine, hence aqua regia uses HNO3 as the oxidant instead. Using the stability constant of the AuCl4- complex allows you to calculate that the electrode potential of Au in concentrated chloride medium is below that of HNO3
The gold must be a transparent compound, what happens if you heat the glass to a dull glow ?
The very thin gold leaf is converted to an aqueous solution on the watch glass by NOCl. Where did you NO gas. I wonder what PtF6 would do to Au.
Amazing work as always!!
I bet you could sidestep the condensation issues by having a camera submerged in room temperature water. then you could just dunk the thing and record away..
Maybe there's a probescope that can go underwater (and isn't the cost of a small motorcycle).
Does the reaction of nitrosyl chloride with gold proceed in the same observed manner in a nitrogen atmosphere? I propose atmospheric oxygen and water are playing a role.
Here's my guess: In inert, anhydrous conditions, 1 gold reacts with 4 nitrosyl chloride to make 1 mol nitrosyl tetrachloroaurate (charges not easily drawn on UA-cam, so it's drawn with a • ... but the NO is NO+ and the AuCl4 is AuCl4 -) and 3 mol nitric oxide.
Au + 4 NOCl --> AuCl4-•NO + 3 NO
but you did in an open atmosphere, where more things happen:
1. The evolved NO reacts with atmospheric oxygen further to NOx (visible as the brown gas NO2)
2. Nitrosonium tetrachloroaurate reacts with water to hydrolyze...
AuCl4•NO + H2O --> HAuCl4 + HNO2 (which then decomposes further).
So I believe the residue you see is tetrachloroauric acid... and then some hydrate of it.
@BradSchmor Yep I had the same idea. HNO2 decomposition produces more H2O, and the yellow residue looks exactly like the aqueous chloroauric acid solutions I used to work with!
@@At0mix sort of - only 1/2 a mol of water is evolved from the nitrous acid decomposition for every one consumed during the hydrolysis - so the net is half of a mol water consumption. I believe that under strict conditions the observation of the nitrosonium tetrachloroaurate would be possible, although it might be subject to some sort of disproportionation reactions - rates unknown. These exotic nitrogen salts always fascinate me because some of them are so fleeting, unstable, explosive, etc. Occupying only a tiny fraction of time as we know it, but revealing so much about chemistry itself.
My most used acids in the way I use them 👍
I think at the reaction surface, the solution rose above it's temperature due to the temp of the gold and table n such, and that's when the reaction was stronger. It seemed to have a hard time, especially the more you cooled it down.
It could be said that the description of these systems can be quite complicated. I think that these reactions are uncontrollable ("strong oxidizing environment"), so kinetic parameters rather than thermodynamic ones are decisive. There can be many more products. After exposure to air humidity, even more. In general, it can be said that in systems where chlorine radical is generated and there is an excess of chloride anions, gold dissolves to AuCl4-, perhaps also by various mechanisms of action of oxidants in the reagent. However, if AuCl4- is exposed to an excess of water and a deficiency of chloride anions, it can be hydrolyzed to AuCl3(OH)-. What's on the dish? Maybe? A mixture of many different complex anions Au3+ and cations NO+, H3O+, H9O4+... :) If such a mixture were processed in some traditional way in hydrochloric acid, we would get after crystallization ais one substance like something like H7O3+AuCl4- or H9O4+AuCl4... :)
Why do you need to use the nitrogen sprayer rather than, say, a dry ice/methanol bath (-78.4°C)? The Cl₂ would remain liquid, and the NO a gas; the NOCl would, I expect, crystallize out when its concentration exceeded its solubility in liquid Cl₂. The sprayer's an interesting gadget (I've never seen one before) but it looks like it's a bit fussy, and control over the reaction temperature would be poorer than with a bath.
Has the gold become a residue of chloroauric acid?
That's what I thought too
In my view, comparing the reactivity of nitrosyl chloride, nitryl chloride, and chlorine nitrate will be interesting as well.
Nice work ❤
WOW! Thank you for this exotic video and all your hard work on this!
I am surprised myself at how slowly and unreactively NOCl reacts with Au. I had expected a much faster reaction.
I can add something about the disappearance of gold, which will probably make me unpopular here because I can refer to experience and not to sources: Gold often does not behave as described in the textbook. Gold shows a certain memory awareness in reactions. It is not possible to dissolve and precipitate gold, dissolve and precipitate again (cyclically) without a deviation from the specialist literature occurring.
What is also exciting (and I have learned from my experience) is that the finest gold (e.g. gold foil)/gold compounds are a fairly volatile metal at low temperatures. It likes to evaporate (sublimated). That is totally confusing. Because I had never reached temperatures above 1200°C. After working with gold & its chemical compounds, my chemical extractor was often slightly gold-plated on the inside. This was not visible. It was only when the viewing windows were cleaned from the inside that the gold in the sponge was visible.
There is a video somewhere on YT where someone dissolves 100g of gold and tries to precipitate it. I think I remember that he only gets 97-98g of precipitate. The person who made the video is totally surprised at the loss! The person who made the video thought the 2-3g were still in solution. I am convinced that a large part has evaporated (sublimated). This is totally confusing. I am sure that I will make myself unpopular with this comment because I cannot provide any citations or reviews for this paradoxical phenomenon. It is based solely on my chemical experience.
Dude that's nuts to see gold react with something with any excitement.
The intro music is my fwend!
Oh nice!
The yellow moist residue shall be AuCl, though I never knew NOCl is the active ingredient in aqua regia before watching this excellent video lol 😅
I honestly don't believe it is, I think it is more of a decomposition product of the aqua regia actually.
@@stinooke but it can decompose into two gaseous products only, not moist residue
@@aupotter2584 exactly, which makes is it less likely to be the oxidant
I'd love to see how you get that gold foil back.
The gold is still there. Maybe you could find the solution?
@@hamaljay exactly, it would be hard in this small of a solution but it would be interesting to so see the chemical experiment that results in getting the gold back and seeing what the recovery rate is.
Hey chemical force, Great Video!
I was wondering if halogen azides are really that unstable, I have read on wiki that iodine azide is relatively more stable than other halogen azides.
That beautiful red of Nytrosyl Chloride makes le wonder what would happen if you mixed it with blood?
Isn't that chloroauric acid left behind after the gold has reacted with the NOCl?
Tetrachloroaurate
NO gas with liquid Cl2 right off the bat... curious to know how you produced/sourced the NO
When you added the nitrosyl chloride to the acetylene it looked like you had an intitial reactions, but then it died, was that the reaction fo residual chemicals?
There's easy ways to dissolve gold, and then there are FUN ways! 😄😄
Apparently it involves solid acetylene for some reason
Comparatively tame reactions. Not even shattered glassware this time... 😉
Got gold chloride at the end?
Very very interesting
How about nitryl chloride?
Can you make a video about some dangerous chemicals that are used for analytic chemistry? Something like 2,4-Dinitrophenylhydrazine for example
ncl3 contamination a danger in synthesis of this?
Use aqua regia as a solvent to extract gold from scrapped electronic parts. Can the cost of the solvent cover the price of the extracted gold?
Does the gold turned to chloroauric acid?
Please make a video about 1,dimethylhydrazine
To me the foil appeared to sublimate. I could not tell you why though.
Smart man make danger water turn yellow,smart man make danger yellow water go red,t smart man make water set fire, smart man can make gold go bye bye bye 😂😂😂
You could also react it with other metals and compounds that you usually use in your videos like alkaline metals, sodium borohydride, hydrazine, etc.
If Nitrosyl chloride is readily hydrolysed by water why does the production of Nitrosyl chloride with HCL and HNO3 not decompose almost immediately from water present in the acid as well as the water produced when Nitrosyl chloride itself is made?
Isn't nitrosyl chloride yellow gas? Why liquid nitrosyl choride look like red?
Cool
Nitrosyl flouride?
very cool
the gold leaf is so thin, it just clumped up in the areas where it disolved
i am no chemist but this is what i am guessing happened
Yeah I'm assuming it's still there and didn't somehow vaporise away..
Now we want to see liquified NOF😁
Bro Why ZAR as Title of the video?
Why is the Title ZAR?
🔥🔥🔥🔥🔥🔥🔥🔥🔥🔥🔥🔥
💫
i read "Tar" atfirst lol
Now you just need: cubane monocarboxylic acid, phosgene, TMS azide, DMDO, NaHMDS, and LiHMDS and then you can make octanitrocubane
What do neighbours think about that H2S smell from every video...
It's actually О=N-Cl
Sreetips!!
Chemists are like the elemental computer programmers , They understand the codes (reactions). Just don't make a typo in that line of work! The risks are far worse!
Now try to make NOBr
Reverse ALCHEMY!
Forbidden Kool Aid
But still good
Huey, Dewey and Louie dumped these chemicals into Uncle Scrooge's money pit.
NOCl+Au->AuCl+NO
Epher
We want sulfuryl chloride 😢
Aqua regia with no aqua, pretty
Next up: nitryl chloride