Axt
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Double salts of Organic Acids
Ive attached a German reference for diaceto-diplumbo-bromate (lead acetato-bromate in PATR 2700). Theres also various references in PATR 2700 relating
to the acetates/oxolates with bromate/chlorate/perchlorate. Though I cant remember what its listed under.
Ive had one attempt at the lead acetato-bromate, with this result:
<center><img src="http://www.sciencemadness.org/scipics/axt/lab.jpg">
<a href="http://geocities.com/roguemovies7/">MOVIE</a></center>
I followed the synth as best I could understand, within the reference provided. But substituted KBrO3 with NaBrO3 but kept the same amounts. It will
take experimentation to get the correct ratio of bromate to acetate to get the correct balance in the precipitate. The precipitate that did form puffs
off like blackpowder when ignited, and detonated under an impact of 3kg falling 15-20cm (PETN=40-45cm).
Theres likely a whole range of these double salts, the citrate if it was to possess the ratio 3 bromate:1 citrate would have zero oxygen balance. The
oxolates aren't worth trying, the "fuel" component being oxygen balaced and only providing dead weight.
Want to pull the syth/properties from this reference chemo.
[Edited on 9-12-2005 by Axt]
Attachment: leadacetobromate2.pdf (299kB)
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chemoleo
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lead acetate-bromate (diaceto-diplumbo-bromate)
Good stuff!
According to the german reference (yes, sir! I read it, and important bits extracted here):
***********************
Lead Bromate (Pb(BrO3)2 ) can be prepared iin several ways, obviously by mixing HBrO3 with lead carbonate, or from concentrated solutions of lead
salts with a mixture of KBrO3/HBrO3, or, most importantly here, by reacting Na/KBrO3 with lead acetate in the presence of excess acetic acid.
Lead bromate on its own is a harmless substance, and decomposes at 180 deg C while producing Br2 vapours. Neither shock or friction cause it to
explode.
This comes as no big surprise.
However (there always is one), when the authors made leadbromate according to the last method (KBrO3 + HAc/PbAc2), 500 g of the crystallised putative
lead bromate (this is what the authors were after) exploded, killed one worker, and injured the eyes of one author severely (that's the chemistry
of the good old days...).
This is the preparation:
175 g of KBrO3 are dissolved in 1.5 l hot water, and mixed with a solution of 175 g acetic acid (100%) and 260 g lead acetate hydrate in 2 l water.
The solution remains clear initially.
It is then filtered, cooled down and seeded with a few crystals of lead bromate while rubbing the side of the glass vessel with a glass rod.
Soon after, the solution becomes turbid, and yields a heavy crystalline precipitate, which does not increase anymore after 12 hours in the cold.
The supernatant is decanted or extracted, and discarded (I'd rather add some Na2CO3 to salvage the remaining lead in the form of PbCO3).
The crystalline precipitate is washed with cold water until it is free of acetic acid and Na/K acetate/bromate.
This is dried in a dessicator over H2SO4. Yield is 123 g. (not very good).
The authors note that this 'Weinland''s substance explodes extremely powerfully upon shock, but they also note that the crystallisation
of either the double salt (explosive) or lead bromate on its own did not seem entirely predictable, i.e. seemingly tiny alterations in reaction
conditions produces either pure lead bromate, or a mixture of the double salt with lead bromate (axt you may want to check whether there are two
crystal types).
The authors also note that if one does NOT seed the mixture with lead bromate crystals, a leafy light crystal precipitate occurs upon standing
overnight in the cold, which seems physically different to the heavy prisms from the lead bromate alone. This is mainly the double salt, which has
this explosive nature.
At last, a mixture of lead bromate with 25% lead acetate (it doesnt say whether it is dehydrated) explodes upon on shock, but presumably with much
less force as the degree of mixing is not intramolecular (i.e. similar to KClO3 & sugar or whatever).
Oh, and one more noteworthy point: They state that the explosion of 50mg (caused by shock or heat) is so powerful that a thick-walled container
would shatter!
Pretty impressive, huh?
***********************
For improvements of the above, one might consider to use much smaller volumes, so that the solution is much more concentrated - which should
precipitate more (greater yield).
I'm not sure though whether double salts with any organic acid could be formed (you mentioned citric acid), as not all necessarily crystallise as
a double salt rather than the mixture of the Pb-bromate and Pb-organic acid.
But then, why not try? 
Also - such explosive double salts, wouldnt they, in principle, also be possible with much smaller divalent metal ions, such as calcium etc?
[Edited on 4-12-2004 by chemoleo]
Never Stop to Begin, and Never Begin to Stop...
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neutrino
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Logically, yes, but I doubt that it would work in practice. For example, by that reasoning, sodium azide should be a powerful primary explosive
because lead azide is, but in practice, it doesn’t really explode at all.
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Axt
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Thanks for the translation 
The precipitate I recieved had no real structure to its crystals ranging in size from very fine to quite large, I've no microscope but its most
likely the impure mixture the ref. refers to. A greater concentration of acetic acid may help since its only going to be the bromate or the double
salt since they are relatively insoluble (compared to its acetate).
As for the salts of calcium/sodium etc, isn't sodium acetate + potassium nitrate a "fulminating" powder, exploded when melted together?
Ive never tried it, but I wrote it down from somewhere.
Theres also the sodium benzoate / lead nitrate salt. Check PATR for the entry "Oxybenzoic Acid, nitrated lead salt" page O55, formed from
Lead nitrate and sodium benzoate. I believe this is formed under a simular mechanism. Even though its mentioned as a "nitro" compound (Pb
trinitro-m-oxybenzoate), they may also be confusing itr with the salt of trinitrobenzoic acid, but not so likely, due to only one reference being
given.
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IPN
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About that lead nitrate/sodium benzoate complex, there was a synthesis for it in megalomanias explosive informania page.
Heres a copy of it: http://koti.mbnet.fi/otto2000/oxybenzoate.htm
It's basicly just copied from the PATR..
There was also some discussion about it at roguesci. Here are copies of the threads:
http://koti.mbnet.fi/otto2000/thread1.htm
http://koti.mbnet.fi/otto2000/thread2.htm
[Edited on 5.12.2004 by IPN]
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woelen
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I found this very old thread on sciencemadness and thought it would be a nice thing to try this myself. I did two experiments:
1: Preparation of lead bromate
-----------------------------------
Take approximately 0.25 grams of lead nitrate and dissolve in a few ml of water. Add one drop of very dilute nitric acid (maybe 5% or so). Apply a
little heat to dissolve the solid more quickly. Allow the solution to cool down. No crystals separate, a clear liquid is obtained.
Take approximately 0.25 grams of sodium bromate and dissolve in a little water. Add so much water that all of the solid dissolves.
Mix the two liquids: Fairly quickly, a compact white precipitate is formed. Heat the liquid again, until boiling. The solid dissolves completely.
Next, set the liquid aside for a full day in a cold room.
After one day, a lot of crystalline solid has settled at the bottom and there also are needle-like crystals, sticking at the surface, which with a
little swirling fall down to the bottle.
Filter the liquid with the crystals and rinse with a few ml of ice cold water. Let the solid dry for one day in a warm place, free of dust. The result
is appr. 250 mg of white crystalline solid. The crystals have a length of 2 mm or so and a thickness of almost 1 mm.
If some of the crystals are put in a test tube and heated, then they decompose, giving clearly visible bromine vapor. A black solid remains behind. I
also tried putting some of the crystals on a metal spatula, and putting them in a flame. Again, the white crystals decompose, leaving a black solid.
On much stronger heating, the black material turns red/orange and on cooling down it turns off-white/pale brown.
No energetic properties are displayed by the crystals, when heated alone. I also tried a mix of some of the crunched crystals with red phosphorus.
This mix is very sensitive. A single tap with a glass rod causes the mix to ignite, which quickly burns, like black powder.
2: preparation of the lead bromate acetate double salt
-------------------------------------------------------------
Take appr. 0.3 grams of basic lead acetate (according to label its composition is close to Pb(OH)1.15 (CH3COOH)0.85 )
Add this to a few ml of 30% CH3COOH. This gives a clear colorless solution.
In a separate test tube dissolve approximately 0.3 grams of KBrO3 in lukewarm water.
Mix the two solutions.
Initially, no precipitate is formed, but one day later, there is a small amount of white crystals. The amount is only low, appr. 100 mg. Separate the
crystals, dry on filter paper and allow to dry for one day.
The result is a fine crystalline powder. The crystals are small (maybe 0.5 mm, and look more compact, they are no needles).
When these crystals are put on a metal spatula and put in a flame, then they quickly burn, like a mix of KClO3 and sulphur, but with a quite bright
beautiful grey/white light and giving off white smoke. In a fireworks display, they would give a really remarkable grey/white flame color, not the
hard white of magnesium.
The crystals definitely are energetic, they burn quickly. I did not do any tests with hitting or ignition in confined spaces, but the unconfined
powder is very easily ignited. I think that I made the lead acetate bromate double salt, Pb(CH3COO)(BrO3).
____________________________________________
I think that pure lead bromate decomposes to PbO2 (very dark brown), O2 and Br2 and that on further heating the PbO2 decomposes to PbO (or maybe some
Pb3O4 as well, giving an orange color).
The double salt has an internal redox reaction, with bromate being the oxidizer and acetate being the fuel. The white smoke most likely is a mix of
PbBr2 and PbO.
[Edited on 14-4-21 by woelen]
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