Silver acetylide - a word of warning

[Microtek]

In a few posts I have advocated the use of silver acetylide as a primary explosive in caps. This explosive has desirable characteristics such as immediate DDT in arbitrarily small amounts (even in the open), good initiating ability (as little as 0.06 g to initiate MHN) and low sensitivity to impact (I have not been able to initiate it with a hammer).
Unfortunately, I have now discovered a flaw with this material:
It seems to be prone to form large crystals when made with very pure silver, and these large crystals detonate when broken.
This is my hypothesis, and has not been tested fully - results will follow, but when I made a batch with 100% pure silver, it exploded when I carefully shifted the crystals to brake them up. Fortunately, SA is a very weak explosive and the detonation of about 0.5 g failed to break the thin plastic dish that it sat on. Further testing included hammering the SA on my anvil, which produced no explosion, and drying it fully in the air, which darkens it (probably due to oxidation) and makes it contract.
After this drying process, it no longer exhibited this instability.
At the moment I'm working with the supposition that the impurities in the silver that I used in earlier batches interfered with the crystal growth. If this was the case, it might be possible to use a procedure similar to that used in the process for making lead azide.

[mongo blongo]

Yea you mean using dextrin? That should work.
I think it is due to inner tension inside the crystals like with Lead Azide.

------------------
AAARRRRRHHH! My beautiful eyes! It burns!
The goggles do nothing!AAARRRRRHHH!

[EventHorizon]

If shifting the crystals to break them up caused detonation presumeably because of breaking crystals...how can hitting them with a hammer not break a crystal causeing detonation? http://theforum.virtualave.net/ubb/smilies/confused.gif

Also, what kind of storage/shelf life does this material have? (in your experience)

------------------
"Chance favors a prepared mind" - Louis Pasteur
"Happiness is a large pile of links." - Me
PGP ID 0x147CEF54

[nbk2000]

Silver azide is used to make thin film detonator for military weapons and is superior to lead azide in performance and safety.

------------------
"I have begun evil, I shall end evil. That is the end that awaits me."

Go here (http://briefcase.yahoo.com/nbk2k) to download the NBK2000 files and videos.

[CodeMason]

Ag₂C₂ -> 2Ag + 2C
As you can see this "explosive" merely breaks apart into very fine particulate carbon and silver, and thus no gaseous products. Its explosive force all comes from the heat from the breakdown of the C<u>=</u>C bond which heats up air around it rapidly so it expands, creating a small shockwave (this is why silver acetylide is preferred in pop rocks, it may be poisonous, but not very dangerous as an explosive to handle for kiddies). Rapid heating and the sending of heavy metal particles into an insensitive explosive are what gives it is initiatory properties. In the military it is almost always a double salts with AgNO₃^-, this increases its explosive power a lot, and hence the name "double salts". http://theforum.virtualave.net/ubb/smilies/smile.gif

------------------
Visit my website (in development): http://codemason.cjb.net

[mongo blongo]

EventHorizon That's a good point! Do you mean that you tried detonation with a hammer with the pure SA or the impure or both with no luck? If it was the pure SA it should have been set off right?
NBK- I have never looked into silver azide do you think it could be made by reacting sodium azide with silver nitrate?



------------------
AAARRRRRHHH! My beautiful eyes! It burns!
The goggles do nothing!AAARRRRRHHH!

[nbk2000]

I don't know if Ag azide is water soluble. If it is, then you'll need to seperate it from the sodium nitrate.

Some points about silver azide:

AgN3 and PbN3 are about equal in friction
sensitivity

The electrostatic sensitivity of AgN3 is about 10 times less than that of PbN3

With AgN3 is no danger for a chemical forming
into Copperazide

The relative energy output of AgN3 is higher than of PbN3

AgN3 has very good chemical stability

Handling of AgN3 is more sensitive than PbN3
during manufacturing

------------------
"I have begun evil, I shall end evil. That is the end that awaits me."

Go here (http://briefcase.yahoo.com/nbk2k) to download the NBK2000 files and videos.

[Microtek]

Yes it is quite puzzling that hammering it does not cause an explosion. I have done that test repeatedly with both the pure and the contaminated substance. After hammering, I have touched a flame to it which causes immediate detonation.
Shelf life is excellent; I have had a tiny sample of the original batch lying exposed to air and light since I made it, and it still works as good as ever ( I think it's been about four months ).
With regards to the double salts, I haven't really got it to work ( though maybe that process is more sensitive to impurities in the silver ), it just deflagrates when ignited.
I am considering another way to desensitize the SA: I have tried using the process for SA to make copper acetylide simply by sustituting copper for silver, but the product is not very impressive. It is somewhat impact sensitive but not very much so, I suspect that dissolving elemental copper in nitric acid does not give the right oxidation stage. I seem to recall that copper is often used to alloy with silver, so if the impurity in the cutlery that I used previously was copper, it should be possible to dissolve a little copper along with the silver and then basify this solution and bubble acetylene through.

[tvs17]

nkb2000, can you tell me what silver azide has to do with the question about silver acetylide?
And by the way it is Pb(N3)2 not PbN3.

(Well...It's got silver in it, doesn't it?

It's also a primary explosive, used in detonators, and anything else I fucking want it to be.

Any other stupid questions?

PS: The info (including PbN3) was directly cut and pasted from the military contractors PDF about thin film detonator construction, so if they flubbed it (HIGHLY unlikely) tell it to them, not me.

NBK2000)

[This message has been edited by nbk2000 (edited 11-17-2001).]

[a_bab]

Oooops...

[Microtek]

I recently read an article on triboluminisence in a layman's magazine. It said that when you break crystals of many common materials, you divide the charge so that you have a surplus of negative charge on one side of the break and a surplus of positive charge on the other. If the potential is big enough, electrons leap across the gap, creating a spark.
This apparantly happens when you break sugar cubes, when you open some self-adhesive envelopes and in many other common instances.
This would go some way to explain why hammering the SA doesn't cause it to detonate, but shifting and breaking it carefully does; the crystal surfaces doesn't really come apart when you hit it with a hammer. Also, the article said that electrically isolating materials were more prone to triboluminisence than conducting ones, so maybe when the SA breaks down a little over time and produces elemental silver and carbon, it becomes conducting enough to limit the sparking.

[xabxulu]

Please be very carefull with any primaries "supposed" to be stable ! Two batchs of silver double salts, one done by the "standard procedure" (silver metal in HNO3), and another from silver nitrate diluted in water, all two very insensitive from shock (with a big hammer !!!) after synthesis, are became very sensitive some month later !!! (with a little hammer this time ;) ). As sensitive as my last sentence was long and laborious :rolleyes: !

If anyone can explain me what I did wrong, I would be happy. I stocked these in film cans in a place where the temperature is unstable (could be that ?)


Thanks.

[kingspaz]

i don't think you did anything wrong if the stuff worked initially. i have about 20g of the stuff that i made about 4-6 months ago. i did no initial test of sensitivity after initial production so have no real comparison but i may hit some with a hammer tomorrow anyway.

did you observe any colour change during storage?

[xabxulu]

First of all, thanks for the reply. Yes, the initial colour of the batch made from silver nitrate was green/yellow, and now it is white with some black (stored in a transparent film can). The other was grey, and I think it is a little more white now (stored in opaque film can). I'll verify that tomorrow, and do some sensitivity tests more precisely. I hope my english is not too bad, if yes, don't hesitate to correct me ;) !!!

[kingspaz]

in me experience the silver double salts were creamy white to begin with and they gradually darkened over the course of a few days until they reached a dark grey colour with white speckles. over this period i noticed a marked increase in violence of detonation and sensitivity to flame.

[Mr Cool]

I just had a clean out of my lab, and found an opaque plastic tub containing some silver acetylide / double salts under distilled water, prepared by bubbling acetylene through aqueous silver nitrate. There was also some free nitric acid in the reaction, though not much, since I leave my silver nitrate slightly damp with nitric acid. I've heard it keeps better that way. After making it, I would have decanted off the solution, washed it with distilled water, and transferred it to the tub, with more distilled water.
It was still a very light grey colour, and behaved exactly the same as the day it was made as far as I can tell.
So I recommend that you keep it away from light and air if you're storing it.

Edit: I can't actually remember when it was made, but I think it was probably about a year ago. It was made with .999 silver and the usual lab-grade 70% HNO3, so it was very pure, and was in the form of a very fine (amorphous?) powder.

[xabxulu]

I think I had a LITTLE "hover-estimate"(?) the unsafety of my product, because I have been able to ram a little of it in a plastic straw safely (always with ears and eyes protections !!), but that's clear that it changed in his sensitivity. Next time I'll try your method of stockage Mr Cool !



Thanks

[ProdigyChild]

I recently produced small amounts of silver acetylide, by bubbling acetylene thorugh (cold) AgNO3 solutions. I tried plain (a) AgNO3 solution, (b) AgNO3 + NH3 solution and (c) Ag2O + NH3 solution.

From all three solutions a white precipate was formed. I filtered and dried it.
All three products are light sensitive and become gray.
All three products are explosive, but product (c) noticeable weaker than (a) and (b).
All three products are insensitive to friction and hammering.

I put a minute amount on a heater plate. The white powder turned brown and black, but did not explode. The black remainder is still explosive and sensitive to flame.
Then, when trying to remove some of the dark powder from the heating plate, the powder exploded right when I touched it with a drinking straw (PE plastic)! :eek:
First time it exploded "without reason".

I decided to carefully grind a few crumbs of the white product (a) with rounded aluminium bar. No problem. When I cleaned the aluminium bar with a 30degrees cut drinking straw, I noticed a flash! :eek: The 1mg of Ag2C2 that sticked to the bar exploded! Second time it exploded "without reason".
That was the time I got contemplative about Ag2C2 and handled it with more care.

Today - 3 days after - I determined the spark sensitivity of product (a).
I've got a few devices for playing with high voltage.
First experiment: Tesla coil like device producing (60kHz) high voltage, ideally suited for cold discharges (faint, deep blue light surounding conductors or conducturs coated with dielectric). Literally **every** contact of Ag2C2 with a cold discharge lead to an immediate detonation of the material. Acetone peroxide did not ignite from such. Needless to say, what happened when Ag2C2 was exposed to a hot arclet.

Ag2C2 also detonates on **every** attempt to ignite it with a cigarette lighter piezo.

Second experiment: static charges.
I was really impressed by the sensitivity and decided to check for Ag2C2s sensitivity to static charges. I used a voltage multiplier (Cockcroft-Walton). Positive pole connected to earth, negative pole as charger. I charged a paper clip to no more than 2000V and touched a small amount (1mmx1mmx0.5mm) of Ag2C2.
Believe it or not - it exploded! In 5 times out of 5.
What's the capacitance of a paper clip? 10pF, 1pF or even less? At least its much less than the capacitance of a spoon, a knife, a metal wire or a cable. If any part of your equipment gets charged by static and you touch the Ag2C2 with that part, the Ag2C2 WILL go off. The energy to set it off is a few u-Joules. Almost nothing.

OK. Blame me for not using 80-90 degrees celsius when preparing the Ag2C2. Problably I got the less desirable, less powerful but more sensitive Ag2C2, not the double salt. But can you ensure, not to have traces of that undesirable product in your double salt product?

Are you all using ESD-protection when experimenting with silver acetylide?
I consider it so MUCH MORE dangerous than AP.

[a_bab]

I fully agree with the static sensitivity on Ag2C2 as I had maybe 1 gram of it in my hand going off. It was stored in a plastic can used for drugs (kind of film cans) and I was removing the label (made of paper) when it went off. I concluded then it must have been due to the creation of static electricity and now you give me the confirmation. It was pretty painfull. Bruises and some mild cuts due to the plastic shrapnel, and a black hand. AND ringing ears for some hours.

[Exothermic]

Ok, sorry for opening up an old thread but I haven't been able to find any information about this.

I have heard people saying that they have been able to store silver acetylide under water in a test tube for up to a year.

Although I have no intention to keep it for that long, I was trying to find out if temp. Would affect the silver acetylide. As this would be stored inside my lab and during the hot summer months it can reach up to 45 degrees Celsius in there.

Personally I do not feel that it will affect it (I.e. no spontaneous detonation etc.). I would like to know from others though.

[Charles Owlen Picket]

In so far as sources I am familiar with discuss the sensitivity of Ag2C2 the range form 0-50 C would not detonate the material. However, this is a silver salt(s) and UV as well as the previously mention static certainly will have some impact on it's safety and longevity. [See USPO search for "copper carbide & detonator" which will get you some patents on the use of acetylide energetic salts & their use in industry.]

The "big-picture" concept is that it is best not to store these materials dry. The facts that have been documented with a variety of primary-type materials are that sensitivity will most always increase when the material is dry and that sensitivity decreases (to a degree) when moist, etc. But the impact in storage from temp fluctuations becomes an issue when those fluctuations are rapid or reach a certain degree. However generalizing is very unproductive. - There are differing salts that can be termed "Ag2C2" as you have read.

Within this thread is a post that addresses what significant heat imposes on Ag2C2. A search of the past posts did address some issues when the material is in storage. The overwhelming majority of cases point to the range of initiation temp as being much higher and that sensitivity factors alter with exposure when dry to electrical, UV, and high heat (well over 45C) stimulus.

Personally, I have seen Ag2C2 stored in water for about 2 years in temp of 40C + with no problem. However your questions begs for more info regarding storage & overall conditions related.

I don't know if one year is necromancy. But I have read that necromancy is a crime. - Particularly when rigor sets in. (I'm kidding, of course, but this then points to a question of when to start a new thread and when to continue an existing one...)

[nbk2000]

Necromancy is bringing up an old thread for the purpose of saying or asking something stupid.

Things like 'Me too' or dumb n00b comments, or asking questions of someone who hasn't posted in years, result in a ban.

Posting a relevant post in the only existing, or most relevant thread, even if it is several years old, is not Necromancy, and is preferred to creating a new thread.

[Wydarr]

I have a very "precious" friend, that has had a very intimate encounter with the silver acetylide. The short story is that he was stupidly mixing silver and copper acetylide (some 50g) with a screwdriver in a ceramic dish, and the shit went kaboom. The reason i say he is precious, is that ever since the incident, his left hand and belly are full of tiny particles of silver, copper and carbon embedded under the skin, which gives him a unique appearance.

[truonggiang_male90]

The SA is Fucking unstable, I had an accident when working with it, but nothing happened with me. I crushed it under water and it exploded. The jar was broken and the remain water become to black (with Carbon in it).....
--------------
This is a video on testing SA with a flame, it exploded with a lound crack sound
http://www.youtube.com/watch?v=TXbSSB0G6ow

[Charles Owlen Picket]

Crushing an energetic material is not a determinate of instability. The stimulus of crushing provides initiation in some of the most stable primaries ever synthesized.

Wherein a statement that directs a result from a stimulus (crushing) to that of initiation is a standard of sensitivity.....not a determinate of stability.

Crush a primary and it initiates: that is in no manner a determinate of stability.

[Exothermic]

Pure silver acetylide (AgC2) is extremely sensitive from what I have read. However it's counter-part the double salt (AgC2*AgNO3) is alot less sensitive and overall more powerful.
It tends to be the case that most people think they are the same compound. So that youtube video is most likely showing double salts detonating, not pure silver acetylide.

[Enkidu]

i crushed it under water and it exploded.

SwiE has crushed MOIST silver acetylide many, many times with no problem. (SwiE has also smacked it with a hammer and briefly put a lit match on it. Nothing happens.) Crushing DRY silver acetylide (whether under water or not) is just plain dumb.

Wherein a statement that directs a result from a stimulus (crushing) to that of initiation is a standard of sensitivity.....not a determinate of stability.

Nice catch.

[totenkov]

I just tried to make a new batch of SA and am real pissed off :(. I am using bought 18 molar silver nitrate and acetylene gas from my O/A setup. I ran the acetylene through the solution and it turned the white within seconds. I ran the gas for about 40 seconds and then let it sit for 10 minutes. I then attempted to filter the solution to collect the yeild only the entire solution went straight through the filter, nothing was collected. I used about 15 mL of AgNO3 and 45mLs water.

I then thought that maybe I didn't run the acetylene for long enough and turned it back on. After the solution began to turn a browny grey. I copied brainfevers method (the whole thing was done in aqueous nitric acid). And I see that his SA settled on the bottom of the graduated cylinder. Mine stays suspended in the mix and simply wont filter, What the hell happend?! Its out in my lab now, should I dump it?

[Charles Owlen Picket]

Only my opinion but IF the LENGTH OF TIME in introducing the acetylene gas was long enough and the amount was in proportion....look to the quality of the gas itself.

The highest yields and the best quality product I have ever seen was utilizing calcium carbide as a source for acetylene gas. This virtually guaranteed that the above issues were done away with.