Sciencemadness Discussion Board

Silver acetylide/nitrate

Nevermore - 20-9-2003 at 12:40

I wonder if is possible to make double salts having silver but HNO3.
I was thinking about a preparation "on the field" of some HNO3 by mixing concentrated sulfuric and ammonium nitrate, but im not sure if what i will obtain will be pure enough to be useful as nitric acid or if is needed nitric acid free of sulfuric, also the formation of ammonium sulfate would interfere in the reaction?
Is it needed to make the salt neutral for storage or i can store acidic, and if yes, what should i use to make it neutral and doesn't react with?

kingspaz - 20-9-2003 at 13:00

using xNO3 + H2SO4 doesn't work in my experience. it does however make a very weakly explosive complex of silver sulphate though.

i could be wrong on this but i think it reacts with bases releasing acetyene.

as for making it neutral i think a good washing with lots of water will suffice, althoughi haven't conducted any tests yet to do with this. i plan to next time my double salts supply runs out.

Madog - 20-9-2003 at 14:43

hm, i would try getting Ca(NO3)2 or Pb(NO3)2 and useing that to make the HNO3 and diluteing it then filtering, then disolve the silver.

the other ions are going to cause silver salts of them to precipitate and/or cause the formation of unwanted complexes. as kingspaz said

Nevermore - 17-10-2003 at 07:47

Got some carbide today, there is only one supplier left in the town, the price was rather cheap! 2 bucks for one kg first quality big rocks not even a little white powder!
I managed some Ag2C2*AgNO3, took 50 ml AgNO3 saturated solution in HNO3 and i diluited in triple volume distilled water, then i took a small carbide stone and bubbled all the gas inside the solution, in around 20 seconds the solution turned white, and before the gas stopped bubbling everything was a thick white slurry, definitely a spectacular yeld.
Like Madog told me the copper impurities doesn't react, in fact the filtering liquid has still a green colour, and if i bubble again nothing more precipitate.

[Edited on 17/10/2003 by Nevermore]

froot - 23-10-2003 at 02:33

I recently made some silver acetylide, using 55% HNO3 and silver obtained from old 3 phase electric contactors. The contact points are pads brazed onto the copper bars and contain an appreciable amount of silver in the alloy.

The nitric acid with the 'silver' turned green and a precipitate also formed. (heating the concoction would probably speed it up). The green liquid was separated from the solids which then turned blue after a while??? Acetylene bubbled through and bingo, the white precipitate.
Turns grey when dry and very impressive. Still testing.

Nevermore - 23-10-2003 at 10:02

one of the strange thing i saw about this sinth is this:
i made a large batch of silver nitrate in hno3, some copper was present so the solution turned a bright green, however, i made a first small batch of about 50 ml solution, i got a fair yeld of snowy white precipitate, dusty like talc powder.
The second batch i made was approx the same amount, just i diluite more with distilled water, the yeld was more than times, but the product is not white but dirt gray, a very thin powder..
I washed both batches and at now i am drying the second one over an hot plate (50°C) to check what is and if there is any difference with the first one, since exactly the same procedure has been followed.

froot - 24-10-2003 at 20:49

Silver acetylide, hotplate, 50 degrees? please be careful. Especially with a larger batch. I would tend to assume the sensitivity to even existing multiplies at higher temperatures.
I've found that with my batch there is very high sensitivity to heat, and so far nothing to friction- so far!

Nevermore - 25-10-2003 at 02:52

No difference has been seen, after a while the product turned white like usual, i wonder what it was, maybe the light?
btw my large batch are always under 2 grams, and before touching anything i let it cool down.
Anyway the salts are insensitive to friction and to hit.
sensitive to flame, but not so much to heat.

froot - 27-10-2003 at 00:38

With regards to the different yields that you're getting, a few questions immediatly come to mind.
Does C2H2 react with HNO3, therefore acetylene being redirected from making Ag2C2 to something else that inhibits some yeild.
Maybe pH plays a part. I have another batch going, and will try neutralising solution and compare yields, NH4OH perhaps?

Nevermore - 27-10-2003 at 06:04

your idea is interesting, however by bubbling acethylene in a neutral or basic solution is more likely to get pure Ag2C2 instead of double salts, i tested with litmus and the solution i used is highly acid, ph less than 2.
I don't really know why happens to have different yelds, maybe the first time i didn't use enough acethylene, or the carbide are more soluble in stronger HNO3..

froot - 27-10-2003 at 07:02

I assume we'd rather have double salts than pure Ag2C2. (I'm not sure how the pure Ag2C2 properties differ from DS) From what you said it seems that the double salt/pure Ag2C2 ratio produced is very dependant on pH, or the molar amount of C2H2 that reacted.
So (theory) if you had a solution with a pH of say 3, you'd be sure to have say 70% double salt in the precipitate, no matter how much acetylene you bubble thru. Or if the pH is above a certain level you just get Ag2C2.
And if this theory is true, would the properties of the product vary. How close can we get to the perfect primary? Just questions running through my head.

Nevermore - 27-10-2003 at 07:10

well, for what i know, Ag2C2 and double salts are very similar, being DS a little less sensitive and giving out more gas output.
But i don't think the difference is so evident..

froot - 29-10-2003 at 07:54

I've left my second batch unfinished. After you said that neutralising makes pure Ag2C2 I decided I could probable put it to better use.
I have a theory -again- that hopefully the real chemical folks could help us with.
A while ago I read the (Mr. Anonymous: azo-clathrate primaries) thread presented by Pulverone - exellent thread!- and I thought maybe concepts there could be used here.
Either while synthesising Ag2C2.AgNO3 or substituting one of the precursers in that thread with the above?!!?

Nevermore - 31-10-2003 at 07:18

you can acidify easily by some HNO3
DS are great, if they had a better yeld and if silver was less expensive then they were my only det!

unionised - 2-11-2003 at 09:06

I seem to remember an old chem. text book saying that you should destroy acetylides by treating them with HNO3.
Ag2C2 +2 HNO3 --> 2 AgNO3 + C2H2
(This is the equivalent of disolving a carbonate in acid)
The only time I made the copper and silver salts of acetylene I used a solution of the metal (as the monovalent ion) in aqueous ammonia.

hodges - 29-4-2004 at 14:23

When making silver acetylide, would it be possible to simply drop a bit of CaC2 into a dilute AgNO3 solution, as opposed to creating an aparatus to bubble the acetylene through? It seems to me this should work. A direct replacement may occur, with silver nitrate plus calcium carbide producing silver carbide plus calcium nitride. If this does not occur, the CaC2 would simply react with the water to produce acetylene, which would bubble through the solution to produce silver carbide. The calcium oxide would react with the the liberated nitrate to again produce calcium nitrate. Calcium nitrate is quite soluable whereas silver carbide is not, so I think this should work. Any thoughts?

chemoleo - 29-4-2004 at 14:40

I don't see why it shouldnt work.
Normally acetylene is bubbled through the AgNO3 solution, so why not adding calcium carbide directly?
The only bigger problem I can see is that CaC2 is normally delivered in big chunks. Adding this to a bucked of AgNO3 solution will almost certainly lead to the explosive evolution of gases (not literally explosive). So if you try it, add TINY grains, one at a time, until it has disappeared.

"Direct method"

forundretfrede - 30-4-2004 at 03:33

If you dump the carbide directly into your solution, you will get problems.
The carbide reacts to produce calcium hydroxide, this will neutralize your acid, and then you will have a precipitate of moderately insoluble hydroxide mixed with the product you want. When you use the gas from a separate generator, you wont have this problem.
By the way, technical grade carbide is NOT a clean substance, so youll allso have sand and other impurities as well.

hodges - 7-5-2004 at 14:18

I made about 0.15g of Ag2C2 using a NH4OH/AgNO3 solution. I bubbled the C2H2 through the solution using a small tube, and didn't try adding the CaC2 directly to the solution.

I got a lot of spongy gray precipitate. I let two small pieces, about 0.01g each, dry. While still drying I set one of them off with a barbecue lighter. The dry part detonated with a weak bang; the wet part did not. Once completely dry the pieces shrank considerably. Each was really just a speck, but when ignited made a very loud bang.

I destroyed the rest of the the Ag2C2 by adding HCl until no more C2H2 was evolved. I never felt unsafe with the substance, its just that even the smallest amount I could use still makes a very loud bang, and I don't wish to annoy my neighbors and/or call attention to myself. With other energetic materials such as Ag3N and NI3 I have been able to get the bang down to something reasonable (like that of a toy cap) by using very small amounts. But it seems Ag2C2 is loud no matter how small the amount. Which is pretty amazing given that no gasses are evolved by the reaction.

Nevermore - 15-5-2004 at 08:54

also you can easily find that is very weak, sometime not able to pierce light cardboard...
this compound has the interesting quality of detonating in a very small amount..
Other compounds usually detonate only if the weight is up a minimum, but this doesn't :D

hodges - 15-5-2004 at 12:35

Actually, all the explosive silver compounds seem to do this (detonate even in tiny amounts). Silver acetylide, silver nitride, silver fulminate.... Likewise with the gold compounds. Must be a thing about heavy metals.

Silver Acetylide

Dream of the iris - 21-12-2005 at 22:33

I'm thinking about synthing this explosive soon, since I just recently got some silver and calcium carbide. Anyone have any expirence with this?

stricnine - 22-12-2005 at 06:50

Yep: bubble the acetylene through a silver nitrate solution. Precipitate forms. Filter the stuff and dry it (NOT with a flame! - or the joy will go off not where you want). The thing is DARN sensitive, so be careful. The dry silver acetylide will explode by scratching it gently with a glass rod. Try with small quantities to learn about it. Heard of a guy who took a test tube full of it to school in his chest pocket, and then they had to remove the glass shrapnel from his lungs. What a waste of a test tube!

pihop - 22-12-2005 at 08:42

I wouldn't even get close to any kind of acetylides.

You can always fill a baloong with acetylene and light it with a long stick.

Dream of the iris - 22-12-2005 at 09:42

I thought this explosive was less sensitive then AP. I'm trying to find another primary to use instead of AP and SA seems like a fitting choice, unless it's more sensitive then AP.

[Edited on 22-12-2005 by Dream of the iris]

moonclub - 22-12-2005 at 10:48

Ag2C2.AgNO3 is better than Ag2C2 - L. I. Bagal. Do not use only AgNO3, it's better to add some HNO3, or if you are using silver + HNO3 - just add some water. It's working good, and I think it's better than organic peroxides. I have some NaN3, so may be soon will try to compare Ag2C2.AgNO3, Ag2C2 and Pb(N3)2.

nitro-genes - 22-12-2005 at 12:39

I second that.
Only make AgC2 for curiosity purpose only. It is not very powerfull or brisant, half a gram of it once failed to break the glass dish it was on, but it will hurt your ears for sure! ;) I doubt if it could even be used to detonate most HE's.
And keep it in the dark as it is, unlike the AgC2*AgNO3 complex, very sensitive to light, and it will darken quickly by the formation of elementry silver

If you're planning to use it as a primary you are indeed better of with the AgC2*AgNO3 complex. It is stated that it is less impact sensitive than Mercury fulminate and less friction sensitive than Lead azide. 100 mg or less will suffice for PETN in a compound detonator.
If you want to used it on it's own, it will become very expensive as you need 2 grams for a #8 detonator. It's much more stable than organic peroxides however. I still have a gram or so, which is kept under destilled water for over a year now, and it is still as white as the day it was made.

The only thing tricky about it's synthesis is the temperature as you bubble the acetylene through the silvernitrate/nitric acid mix. The first batches I made without heating seemed fine at first but darkened after a couple of weeks, @60-75 deg C. I got a stable product, and @90+ deg C. I found the product to darken quickly again. A total of 10% of nitric acid wil suffice, but more is not a problem.

[Edited on 22-12-2005 by nitro-genes]

[Edited on 22-12-2005 by nitro-genes]

Dream of the iris - 22-12-2005 at 14:43

So, temperature control is vital to the synthesis?

Also, AgC2*AgNO3 complex?

[Edited on 22-12-2005 by Dream of the iris]

nitro-genes - 23-12-2005 at 06:02

Not for AgC2, just bubble acetylene through a silver nitrate solution at room temperature. Cover your reaction vessel in aluminium foil to protect it from light else you will make a finely divided silver suspension mainly.
No need to add ammonia, bubbling through water is much cleaner and quicker. Though I' have read that precipitation from only water also yields a AgC2*AgNO3 complex, I found the product thus obtained not to resemble the nitric acid precipitated complex, which is much less light sensitive...

For the AgC2*AgNO3 from nitric acid there is also no need for close temperature control. Just use hot water from the tap to warm the AgNO3/nitric acid mix while bubbling the acetylene through. Dry on a clean ceramic or glass dish, since the precence of organic material will make it more sensitive to light. Also avoid contact with copper...

Dream of the iris - 23-12-2005 at 17:00

Ok, I get it now. I tried Brainfeverts synthesis and got good results, but, uh, the holes in my filter were too big so I lost all my product :o

Oh well, I'll try again later. At least I know I made it :p

Nevermore - 30-12-2005 at 01:23

holes in the filter???
u can just use a paper tissue and it will be fine!

Dream of the iris - 30-12-2005 at 17:24

I did that yesterday, but most of it is stuck on the filter :p So I'll just wait till it drys.

agent_entropy - 20-8-2006 at 21:48

What is still not clear to me is the actual structure of silver acetylide and the double salt. Can anyone shed some light on this?

For that matter, is the mechanism of the formation of either of these known? If so what is it?

quicksilver - 22-8-2006 at 06:54

The only primary to my knowlege that does not produce gases. Plus the references are clouded with issues concerning the two methods (ammonia or HNO3) that MAY
produce differing results. The structure of the crystal differs from one method to
another as well.

The term double salts may be linked to the free silver nitrate existant in
the primary. However the most common recording of VoD is about 3500.

"The customary precipitate formed by interaction of
acetylene with aqueous silver nitrate solutions has been
considered to have the formula Ag2C2.AgXOat having a
crystal form of fine needles and crosses. We find this
conclusion to be true for only dilute solutions. As the
silver nitrate concentration of the solution is raised above
about 10%, there is a tendency for rhombohedral crystals
to form and above about 25% silver nitrate concentration
the rhombs form to the exclusion of the needles. We
have found these rhombs to have the formula of
Ag2C2*AgNO3 or Ag3C2NO3 "

Background material can be found through:
Federoff, Encyclopedia of Explosives Vol.1 * Kast * Taylor/Rinkenbach

mrtran1224 - 3-9-2006 at 07:38

I was looking over Brainfever's method and apparently organic material causes double salts to decompose. From my understanding organic means the material contains carbon? I am not too sure on what the definition of organic material is, could someone please help me out with this?

Well, if double salts does decompose from organic material( containing carbon from my understanding), and many explosives contain carbon. Does this mean a compound blasting cap with and "organic" explosive as the base charge (I am currently using ETN as my base charge, with acetone peroxide as the primary) will cause any double salts in contact with it to decompose? I am slightly concerned with decomposing double salts, although I only load primaries and finish the caps right before use them.

If double salts does decompose, what does it decompose into, and would decomposing double salts be dangerous in a cap because of the base charge?

quicksilver - 9-9-2006 at 07:21

From that perspective (the use of peroxcides) I WOULD have some concern. That makes sense. But if the use is immediate after construction that would of course make it a non-issue.
But frankly if you are using an ETN base there is NO reason why you need the peroxcide. The hot methanol re-crystalization of ETN will produce needles that are extremely sensitive to detonation and silver acetylid should have no problem at all kicking it off.

hinz - 9-9-2006 at 09:31

mrtran1224, you don't need to worry about the SA to decompose with organic material. I changed from peroxides to SA/MHN as primary for a while. The primary is a 30:70 mixture of MHN/SA and the base charge is MHN alone. The MHN improves the power of the mixture as it gives off gases whereas SA doesn't give any gas, only heat.

The only thing you should avoid are acidic conditions, these will librate the acetylene in the compond over time and leave the acid salt of silver. So the nitrate ester should be washed well.

The primary mixture (a few grams) is still in a plastic tube in my shelf and is as gray as at the time I synthetised it. All caps I made with it worked great, the caps are quite small (5mm in dia and 4cm long) , the primary mixture is in the first 5mm.
Since I know this wonderful primary I wont mess with peroxides any more for sure.

[Edited on 9-9-2006 by hinz]

weknowpyro - 19-4-2007 at 12:13

I have been trying to find out recently but have not been able to find any information about it.
I am storing my silver acetylide in a test tube under water and I was wondering if extreme temp. Of up to 45 degrees centigrade in my lab could make this dangerous (i.e. spontaneous detonation etc.)

The_Davster - 19-4-2007 at 21:55

All acetylides react with water, silver only slowly because of its insolubility, wheras sodium acetylide will reduce water to hydrogen.

I doubt a slightly increased temp will affect stability of that compound, but that is a gut feeling, not based on any readings.

For extra precautions, a block of stryofoam can have holes bored in it for testtube of such material, so if for whatever reason it went off, shrapnel would be contained.

quicksilver - 20-4-2007 at 05:06

A block of Styrofoam is a good idea. Frankly I have seen it stored under a _mix_ of ethanol and water for many months with no mishaps. The guy used vodka and the material dried quickly because of that. You could poor off the water and switch; it would make access faster, etc. Realistically I don't believe 45 C is high enough to present any issue other than evaporation.

copper acetylide tin nitate double salt

AndersHoveland - 12-1-2012 at 15:14

Just a thought, it might be interesting to see if tin(II) nitrate can form an adduct salt with copper acetylide (Cu2C2).
The compound might have a composition similar to Sn(NO3)2*Cu2C2


Basic Stannous Nitrate, with the formula Sn3(OH)4(NO3)2, is a white crystalline substance which is slowly oxidized upon exposure to air, and partially decomposes in pH nuetral water. It is a high explosive, detonating (with an concurrent shower of sparks) when strongly rubbed, hit with a hammer, or heated above 100degC. Thermal decomposition proceeds at 125degC, resulting in formation of SnO2, nitric oxide, and water.

It can be prepared by dissolving tin in dilute nitric acid, then reacting with sodium carbonate, or alternatively, by reaction of tin with a solution of cupric nitrate.

Attempting to evaporate an aqueous solution of Sn(NO3)2 to dryness only results in decomposition, which can in some instances be violent. The decomposition products are mainly SnO2, nitrous oxide, and hydroxylamine, with other oxides of nitrogen also produced.

When AgNO3 reacts with acetylene, a portion of the nitrate ions are displaced and an insoluble basic salt precipitates. Similarly, when Sn(NO3)2 reacts with sodium carbonate, an insoluble basic salt precipitates.


The composition of commonly prepared "silver acetylide" is actually closer to Ag2C2·6AgNO3; forming the Ag2C2·AgNO3 compound requires temperatures above 80degC.

In a similar example of this type of reaction, lead(II) nitrate reacts with aqueous ammonia to precipitate insoluble basic lead nitrate, Pb2O(NO3)2, (which is not explosive).

So one could be inclined to think that perhaps a similar type of "basic" salt could be formed from Ag2C2 and Sn(NO3)2. But actually making this could be problematic, because AgNO3 solution would probably oxidize the Sn+2 ions. Perhaps Cu2C2 could be used instead of the AgC2.

One could react copper(I) oxide with concentrated ammonium hydroxide solution to dissolve it. Unfortunately, the reaction of acid with the copper(I) hydroxide ammonia complex will simply cause it to disproportionate into Cu+2 and elemental copper. The Cu+1 state is also stabilized by chloride ions (such as from hydrochloric acid) but in this case that would contaminate the reaction.


Copper(I) oxide dissolves in concentrated ammonia solution to form the colourless complex [Cu(NH3)2]+, which easily oxidizes in air to the blue [Cu(NH3)4(H2O)2]2+.

Reaction of copper(I) oxide with dilute sulfuric acid will result in the formation of metallic copper,
Cu2O + H2SO4 --> CuSO4 + Cu + H2O

A solution of copper sulfate combined with sodium chloride can dissolve metallic copper,
Cu[+2] + Cu + 4 Cl[-] --> 2 CuCl2[-]

Some Sn(NO3)2 would be added to the copper(I) hydroxide ammonia complex solution, then acetylene would be bubbled in. Hopefully an interesting explosive product would precipitate out.

also found an interesting research paper in the Science Madness Library that describes an explosive double salt hydrate with the composition Ag2C2*(2)AgClO4*(2)H2O

[Edited on 12-1-2012 by AndersHoveland]