Copper-II-sulphide

[Ventsi]

Well it worked, not perfectly but I ended up with a puck of fragile blue-black fibers. They are now drying in the oven and waiting to be weighed.

http://www.wiredforgadgets.com/images/2008/07/myth-confirmed.jpg

[Mumbles]

Benzene hexachloride is NOT a correct name for hexachlorobenzene. Chloride is reserved for ionic salts. It's probably just an archaic name that has persevered, like methylene chloride, ethylene glycol, or amyl alcohol. I think it might be an artifact of how it is prepared. Oddly enough HCB and lindane are prepared the same way, by photochemically reacting benzene and chlorine gas. I think the only difference is what (if any) catalyst is used.

 

Without NMR or mass spec or IR, it might be hard to tell apart, so that is probably how the terms came to be confused. None of the above tests existed when they were first synthesized and characterized.

[Ralph]

the copper sulfide I made (via bubbling hydrogen sulfide through a copper sulfate solution) is now dry what comp should I made (only made a few grams of it beacuse want to try it before I go to the effort of inhaling heaps of rotten egg gas)

[Mumbles]

Did you read a_bab's post? The Weingart reference states that the precipitated form is useless. I think it has a lot to do with crystal structure and stoichiometry.

[Ralph]

yeah but cant hurt in trying

[Mumbles]

Not unless you stand too close to the reaction making it

[a_bab]

Ralph,

 

if you consider making large amounts of CuS then Wengart's method is way easier and less dangrerous.

Frankly speaking, the chances of surviving a large scale synth (above tens of grams) are really low, as I KNOW your equipment is no better than a PET bottle or something close to it. Read this please: http://www.sciencemadness.org/talk/viewthread.php?tid=10491

 

Now, on the formulas using CuS, the old book I cited has lots of formulas, all based on potassium chlorate/calomel. Hopefully another chlorine donor will work, and even better, another oxidizer, as chlorates + sulphides are a no - no. Especialy ones made fram raw sulphur.

[Ralph]

yeah i made some by taking copper powder and sulfur powder but it looked as if it had many differing impurities (on the surface it looked kinda blue on the inside it was more black) so i tried using hydrogen sulphide

[Ventsi]

I had the same experience,the top was distinct dark blue, the rest was close to black. AFAIK the compound can differ in color due to different temperatures pressures, etc.. I have yet to test mine, though I now have 40g of it, if this method worked I'll make a bigger batch for sure.

[a_bab]

The impurities are likely copper carbonates and such. At any rate, they can't be flame contaminants as long as they ARE copper salts.

[Ventsi]

Well I tried to grind the stuff in my mill. Not having any spare media I just went out and got a bag of marbles for it. After 2 hours most of it was a fine consistency though a good deal was in ~40 mesh crystals. Upon trying to crush those up manually I noted how friggin' hard this stuff is. About the same as grinding sand. I should go out and buy some steel balls...

 

I wonder if it could be used as a fuel in some sort of a blue flash much like SbS3 is used with K.chlorate? Could be worth a shot.

[a_bab]

It won't work for sure as a fuel; only Sb2S3 and As sulphides are known to do it, for the reason they are unstable, leaving the reactive sulphur/metaloids behind.

 

Just realising: maybe Sb2O3 could work in dragon eggs? Mumbles?

[Mumbles]

I was reading a thread on UKPS forum and came across some references for copper sulfide. I got bored, so I decided to look up some syntheses.

 

Copper metal + elemental sulfur will work to produce primarily Copper (I) sulfide. The most efficient and chemically pure method is to react elemental copper with a Carbon Disulfide solution sulfur under pressure. Roasting Cu2S with excess sulfur will give a cocktail of compounds.

 

H2S will form an impure copper (II) sulfide. Perhaps a potassium sulfide solution could work a little better without having to deal with H2S. Potassium sulfide can be purchased or made from S8 and KOH.

[Ventsi]

Wait, Mumbles let me get this right. Are you saying the Copper sulfide I made via. heating of S+Cu will give a useless chemical?

If so thats really a bummer, and on the of side, do you know if this Copper salt decomposes Per/Chlorate's?

[Mumbles]

I never said useless, just not Copper (II) sulfide, the desired compound. The "cocktail" of compounds you get while roasting excess sulfur and copper together was not expanded upon by what I read, just stating that it was not a good way to prepare pure CuS. Then again, given what we use it form, it probably wouldn't matter for a colorant, just maybe not quite as consistent. They probably would all work. Nearly all transition metals that I know of catalyze the decomposition of perchlorate or chlorate in some way. Some are better than others. Just as a semi-educated guess, I'd put this on the lower end of the catalytic power spectra.

[PyroMania]

hii I am sry I don't know how to start a new topicc .. Is there some one knows thee composition of pom pom (fireworks)? reply me

[Lagrange]

making potassium (mixed) sulfide from elemental sulfure, take two part water and one part KOH/NaOH and disolve. Add sulfur to the solution and slowly microwave. the alcaline olution will disolve sulfur.

 

add soluble copper salt in and voila! coper sulfide! filter and rince.

 

thanx to this man for inspiration

[Mumbles]

I would certainly not recommend making the sulfide solution in any household microwave. It seems you made quite a jump in logic here. Please be aware that for chemistry purposes thermal energy from a hot plate or flame is NOT the same as microwave energy. They will do vastly different things in many circumstances, and can lead to unexpected and dangerous results.

 

If you look at the images from Weingart that a_bab posted on the 2nd page you will see your method will produce a useless product supposedly, besides being contaminated with a caustic sodium salt.

[Lagrange]

No logic jump on my side, maybe on yours do you understand microwave oven, there's the magnetron wich produce light with a wavelenght of about 122 nm. the wave is then absorbed by water and some dielectric. sulfur and KOH are not absorbind this wavelength. 122 nm is design to be absorbe almost exclusively by the water. some large molecule (fat) can also absorb them. this result in the addition of thermal energy (heat) in water wich is sensibly the same as another source of heat.

 

you may be refering to Microwave chemistry, but this isn't the case here as you can understand very easily from the compound used and produced.

 

by the way, i proposed using potassium salt... and you should try before saying it doesn't work. this is not at all the same as the a_bad method. Maybe read again just to help

 

thanks mumbles to point out possible danger source. i did this very often, the only drawback of using microwave oven is the very small sulfur smell

 

 

About my last post now, storing the yellow mixture is very interesting as the color will fade out with time producing, instead of "virtual potassium (mixed) sulfide" you finaly get , after week, real mixed sulfides of potassium. the method is in part as the quantity of reagent is not so important. Stochiometric equation can be calculate but only as an approximation, since small quantity of sulfite and sulfate of potatium will form. this does NOT change the quality of sulfide generate, just the quantity.

Edited January 24, 2010 by Lagrange

[Mumbles]

I am aware how microwaves work. In the video you referenced, the guy clearly mentions that heating the mixture can speed up the sulfur/hydroxide reaction. It would be common for someone who is not familiar with chemistry to think that heating it on the stove or in the microwave would be the same. I just wanted to make sure it was made apparant that they were not the same.

 

You might be interested to know that sulfur lamps operate at the same frequency, or very close to it, as household microwaves. Slightly different application, but sulfur is microwave active at this frequency. I think you meant to say 0.122 meters not 122 nm by the way. 122nm would be well into the UV range, and not blocked at all by that circular mesh on the microwave door.

 

I only reference the post made by a_bab, that states that precipitated sulfide isn't any good. My blues are fine, so I have no reason to pursue this. You might actually get some copper polysulfides with this method (if excessive sulfur in the alkali), so that might be the trick. H2S produces only mono-sulfides, where as heating copper and sulfur will make polysulfides too.

[Lagrange]

Sulfur do NOT resonate with this frequency of microwave (truely 0.122 meter, sorry) in the solid or simply in the gaseous state nor it will get to plasma in a microwave oven. The presence of oxygen inhibit the sulfur lamp effect in a microwave. it is totaly irrevelent.

 

This precipitation method work perfectly and i wanted to share it, not get in a kid fight about who's right. it is very easy to perform for everyone with drain opener and elemental sulfur, it does not rely on H2S and liquid or gaseous sulfur and i tought it would be usefull to many here (maybe except you?).

 

I propose finishing this here, i understand your opinion of microwave not heating not being the "same". People sould understant that microwave only heat plasma and very specific substance in the non-ionized state. those substances generaly get overheat in microwave wich may be dangerous chemically or physically this doesn't aply easyli to water. the end result is generally heat wich is descrive by molecular movement wich is the same from a microwave or a naked flame.

 

peace

[patience]

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...

[50AE]

Very good topic you discuss here! I'm really in the quest to make the best blue out of K. chlorate and I'll give this CuS synthesis a try. I have some scrap copper from heatsinks, but I could by the powder as well, it isn't expensive.