Copper-II-sulphide

[AdmiralDonSnider]

A pyrotechnic factory-owner, who is a valuable member at Pyroguide, has recently mentioned the use of Copper-II-sulphide (Covellite, CuS) as a blue color producing agent. We were originally talking about paris green, its unavailability and toxicity...He said:

 

"Use Copper Sulphide (CuS) instead of Paris Green. It is also difficult to obtain, but not so poisonous. Its blue is as good as that of Paris Green."

 

This is quite promising given the absence of the acetoarsenite, which may present an issue with a potassium chlorate-based oxidizer system. While ammonium perchlorate blues (e.g. with the new benzoates and acetates) give superb results, they are also an expensive choice for many. CuO and CuOCl both are good substitutes for paris green in case of blue chlorate stars (Paris green was almost exclusively used with chlorate), but it is a by-word among professionals that the color is not as good even with chlorine donors.

 

Has anyone ever heard about the use of CuS in blue stars?

Edited October 1, 2009 by AdmiralDonSnider

[drtoivowillmann]

Dear friend, AdmiralDonSnider:

 

CuS gives a quite good blue for the same reason as the prohibited Coppersulphate does.

Seems to be, not even me as a chemist do have an explanation why, that some elements, like

arsenic (Paris Green) or sulphur, when present in these formulas, somehow mediate the chlorine transfer to the copper.

I tried it and it worked well: only perchlorate, shellac and sulphide gave a good blue.

Copper acetate by far is not the same blue as Paris Green, because their is no arsenic.

Add pure sulphur to any organic blue formula, the blue will be deeper. But I consider sulphid less dangerous than pure sulphur, for there is no sulfuric acid contamination.

 

Today, I use none of them, in formulas with Magnalium and its high burning temperature, metallic copper or its Black Oxide and PVC will do. Magnalium bllues are not so deep as excellent organic ones, but they are so brilliant and this is what today's customers like.

 

Yours truely:

Toivo

[a_bab]

In Weingard's "Pyrotechnics" copper sulphide is also mentioned along with an easy to do synth (basically copper sheets and sulphur, "cooked" in an iron pot IIRC).

 

Another easy synth would be to mix copper powder and sulphur and igniote the mix, so it's not that hard to come by. In the "iron pot" method, obviously thin copper wires would be an easyer option.

 

Still, I would in no way use any sulphide with a chlorate.

 

For some, the fact that the carbonates would sensitize the chlorates is odd, and so it looks indeed. But, I guess it may be because of the sulphides that are likely to be present in the carbonates (it is a known fact that barium carbonate from the pottery store has shitloads of sulphides in it, due to the technological process involved in making it (BaSO4 reduced with coal))

[Ventsi]

This sounds like a excellent weekend project for me and and one of my, "leaning towards pyro" buddies.

 

Could someone provide a formula? I'm really not too good with atomic mass-mole-gram conversions. A PM explaining those would be nice too...

[Mumbles]

This actually makes a lot of sense. Sulfur is added to perchlorate specifically to release the chlorine. It doesn't in general give up much of it's chlorine, instead forming KCl. Sulfur added forms K2S and chlorine gas. The same thing goes with chlorate, even though it does give up some of it's chlorine on it's own. I'd imagine arsenic might do the same thing by being related by a diagonal trend.

[AdmiralDonSnider]

Dear friend, AdmiralDonSnider:

 

CuS gives a quite good blue for the same reason as the prohibited Coppersulphate does.

Seems to be, not even me as a chemist do have an explanation why, that some elements, like

arsenic (Paris Green) or sulphur, when present in these formulas, somehow mediate the chlorine transfer to the copper.

I tried it and it worked well: only perchlorate, shellac and sulphide gave a good blue.

Copper acetate by far is not the same blue as Paris Green, because their is no arsenic.

Add pure sulphur to any organic blue formula, the blue will be deeper. But I consider sulphid less dangerous than pure sulphur, for there is no sulfuric acid contamination.

 

Today, I use none of them, in formulas with Magnalium and its high burning temperature, metallic copper or its Black Oxide and PVC will do. Magnalium bllues are not so deep as excellent organic ones, but they are so brilliant and this is what today's customers like.

 

Yours truely:

Toivo

 

 

Thanks for pointing this out, Toivo. I hope you don´t hold it against me that I put your statements at Pyroguide forward for discussion.

 

Availability seems to be another issue with CuS. It actually is a native ore and hard to synthesize at home (you would need gaseous hydrogen sulphide or so). Other than that I never heard of a commercial source.

[drtoivowillmann]

Thanks for pointing this out, Toivo. I hope you don´t hold it against me that I put your statements at Pyroguide forward for discussion.

 

Dear Friend Admiral Don Snider:

 

Quite the reverse ! You are helping me.

 

You know there is an Amercian Journal called "Pyrotechnica - occasionally published papers".

It's excellent, but only easily available to UScitizens, who live there. I am trying to raise up the discussion

at the levels of that journal, in order to be all the free pyrotechnic international forums virtual substitutes for it.

 

Wherever you spread our discussions, you help me doing so.

 

Thanks,

yours truely:

Toivo

[Ralph]

as a_bab said copper metal and sulphur can be reacted together from a little bit of reading it appears that CuS wont be the only product but also other forms of copper sulphide also my guess is that the surface which is exposed to oxygen would as most sulphides do decompose liberating sulphur dioxide and leave the oxide of the metal (in this case CuO)

 

was a fun reaction to do it burned very quickly and had a very interesting flame colour if you cant get copper powder it can be easily made using copper sulphate and some iron anything from steal wool to iron powder will yeaild lots of nice fine copper powder

[Mumbles]

I got curious and tried looking up a synthesis for it. It's a natural mineral so there arn't many floating around. H2S bubbled into copper solution is about all I found. I'm sure there is a simple way to do it. One could probably make a K2S solution and mix.

 

You might want to go with aluminum to precipitate the copper. You can wash it with NaOH or KOH to remove all the excess aluminum and pretty much everything else.

[Mumbles]

You might as well find a source for HCB too. I hear that is the other thing that really made the old PG formulas so amazing. Then again, I also attribute a factor of old timers reminiscing about how things were so much better back in the old days.

[AdmiralDonSnider]

Off topic- Underground Gadgets has Paris green for anyone wanting to try some of the classic blue formulas for comparison's sake.

 

20$ for 250grams....hmm, I guess he´s a monopolist.

 

You might as well find a source for HCB too. I hear that is the other thing that really made the old PG formulas so amazing. Then again, I also attribute a factor of old timers reminiscing about how things were so much better back in the old days.

 

Keten has BHC, he´s european though. You may be right about the PG "stories", but it´s still amazing to hear how it is missed even by some of the classic authors, not only for its color quality, but also for the characteristics of the stars (cheap chlorate, easy ignition, large flame).

[Miech]

I thought CuS is one of the most insoluble salts around, so precipitation would be an easy and safe way to make it. A copper/sulfur mixture might burn quite violent, so take care if you take this approach instead.

[Ralph]

precipitation wouldn't be so easy because hydrogen sulphide is toxic and smells really bad

[Mumbles]

You might want to find out exactly what Keten has. Benzene Hexachloride and Hexachlorobenzene do not always mean the same thing.

 

http://en.wikipedia.org/wiki/Hexachlorobenzene

http://en.wikipedia.org/wiki/Lindane

[Miech]

precipitation wouldn't be so easy because hydrogen sulphide is toxic and smells really bad

Try precipitation with any random soluble copper salt and potassium sulfide. Copper(II) sulfide is one (if not the) least soluble salts in existance with a solubility of less than 1*10^-6 mole per liter of water.

[AdmiralDonSnider]

You might want to find out exactly what Keten has. Benzene Hexachloride and Hexachlorobenzene do not always mean the same thing.

 

Correct me if I´m wrong, but benzene hexachloride (BHC) and hexachlorobenzene do mean the same, as Lindane is only "erroneously known as benzene hexachloride".

 

Anyway, thanks for pointing this out. BHC and Lindane still seem to be hard to discern: "The gamma BHC which is separated from the industrial products to more than 99% purity is called "Lindane". It is best to use the bi-product from the manufacture of Lindane for firework material." (Shimizu FAST p.151)

 

So is gamma BHC the same as Lindane? As far as I got it the BHC we are looking for only contains a small part of gamma BHC and most of it is alpha BHC...

 

I´m quite sure Keten had true BHC, not Lindane, but I´m unable to find it in his stock now.

[Klaaskroegbaas]

Lindane is not a benzene but a cyclohexane (so no double bonds as in benzene)

 

so hexachlorobenzene and benzene hexachlorid are exactly the same.

Lindane should be called 1,2,3,4,5,6 hexachlorocyclohexane

Edited October 4, 2009 by Klaaskroegbaas

[Mumbles]

Benzene hexachloride is an archaic name if anything. It certainly isn't a chemically accurate name. I was just pointing out an occasional nomenclature error to be aware of. They can both be used for pyro, but I don't know if they have the same properties. Organic strobes specifically come to mind.

[AdmiralDonSnider]

I was just pointing out an occasional nomenclature error to be aware of. They can both be used for pyro, but I don't know if they have the same properties.

 

I know. Thanks a lot for doing so.

[Ventsi]

I think I'll give this thing a go. I have 40g of finely chopped super thin coper wires{think steel wool} and a small flowerpot with a cap.

I'll try the direct heating of Cu & S method inside the fireclay crucible.

 

With a bit of math I found out that the combination should be:

 

64.5g Copper

35.5 Sulfur

=

100 g CuS.

 

Any suggestions as to what to do?

I'm thinking of just sticking it inside a charcoal chimney type setup and leaving it in there for ~30mins.

[NightHawkInLight]

I would use an excess of sulfur, as well as heating for as long as possible. No need to waste reactants because you were in a rush.

[drtoivowillmann]

Lindane is not a benzene but a cyclohexane (so no double bonds as in benzene)

 

so hexachlorobenzene and benzene hexachlorid are exactly the same.

Lindane should be called 1,2,3,4,5,6 hexachlorocyclohexane

 

You are both wrong:

 

Hexachlorobenzene: C6Cl6

"Benzene Hexachloride" is a (chemically wrong, because its no longer aromatic) more trivial than

cientific name for C6H6Cl6.

 

Don't be angry with me:

 

Yours truely:

Toivo

[a_bab]

From Weingart, George W - Pyrotechny

[Ventsi]

Ahh thank you sir.

Seems like me and Mr. Weingart were on the same page.

I'll up the sulfur a bit and heat it for longer I suppose. Dunno why someone would use a iron crucible, my first thought was it would get eaten away instanteniously.

Edited October 8, 2009 by Ventsi

[Klaaskroegbaas]

Hexachlorobenzene: C6Cl6

"Benzene Hexachloride" is a (chemically wrong, because its no longer aromatic) more trivial than

cientific name for C6H6Cl6.

 

benzene hexa chloride and hexachloro benzene are two ways of writing the exact same chemical compound.

 

It's just stupid to say lindane is benzene hexachloride, it is wrong as you say because it needs an (aromatic) benzene structure. Wikipedia also says:

Lindane, also known as erroneously known as benzene hexachloride (BHC)

 

Lindane is a cyclohexane not a benzene to point out my view on this.

 

Hmmmm strange that we are writing this in the CuS topic:P

Edited October 8, 2009 by Klaaskroegbaas