13 replies to this topic

[hosto]

I used to make quite a bit of black powder with potassium nitrate, sulphur and charcoal. This was an excellent mix for producing showers of sparks when put in cardboard tubes. Me and my dad years ago made a whole lot of fireworks one year, and had lots of fun.

A couple of years later, i decided to make a mixture of sodium chlorate, sulphur and charcoal (I didnt grind it together!! I powdered it all first)...then i put it into a bottle and put a rocket fuse in it. My friend and I lit it and ran away (on guy fawkes night)...I was really surprised that it exploded! even without being compressed or compacted. I was expecting a fast burning mixture.

What is it about chlorate over nitrate that caused this to happen? is it like a chain reaction?..i've tried lighting chlorate and sulphur together and it simply burned..but with the charcoal it was really savage.

anyway, just curious..


wish i had some strontium nitrate!! love that bright red colour

[Pyromaster2003]

i always use chlorate black powder for firecrackers and the 'bang' in rockets since i cant get any bloody flash. its pretty dangerous stuff and i never store it. to check out the burn rate of this stuff check the videos sections out on my site and double click on 'Chlorate Black Powder burning'. www.geocities.com/pyromasterman2003/videos

[fusion121]

the chlorate (CLO3-) anion is a better oxidising agent then the nitrate (NO3-) this accounts for the increase the reate of reaction. The chemsitry behind this is due to the fact that, although with the nitrate you have the large entropic driving force of the formation of the nitorgen triple bond, nitrogen oxygen bonds are actually relatively stable due to efficient molecular orbital interaction between the 2p electron orbitals of nitorgen and the 2p electron orbitals of oxygen (the nitrate ion is also further stabalised by resonace). With the chlorate anion however the Cl-O bond is not particularly strong, due to less effiecent overlap of 3p and 2p electron orbitals furthermore the stabalisation due to resonace is less. Baciaclly the difference arises due to the relative strengths of the N-O and CL-O bond lengths the N-O length is 1.24 angstroms whereas the CL-O bondlength is about 1.7 angstroms. The weaker Cl-O bond is more suseptable to cleavage by accepting electron pairs and hence is the more powerful oxidising agent.

[adamw]

Im sure although most of you lot understand this, the simplified answer is, like Fusion said, the chlorate is a better oxidiser. Also, depending on what charcoal you used, it is a much better fuel than sulphur!

Also, making a composition that contains both a chlorate and sulphur (compounds) isn't a wise idea. Read some of the previous discussions on this matter.

[Edited on 28-5-2003 by adamw]

[hosto]

thanks! that was interesting..

PS. never mix conc sulphuric acid and potassium permanganate

[adamw]

Yes you get a nice substance called Permanganic Acid. Basically it will make things combust in quite a nasty way!

[Gor]

Actually the difference is simple....

Potassium nitrate is fertiliser, and sodium chlorate is weedkiller....its bound to be meaner and nastier.

[Edited on 26-6-2003 by Gor]

[pyromaniac]

i like ur thinkin....................
is there a way (no.....not siving it) to rid of the crap and be left with basially pure sodium chlorate?

[adamw]

Not thats worthwhile. Unlucky eh.

[pyromaniac]

:arse:

[shadow]

iv never tried it with sodium chlorate because of the fire supressent that they use in it and have always found that because of this the sodium chlorate burns really slow. any thoughts on this :flames:

[Rhodri]

Why do people insist on using NaClO3 for pyro?

It's poisonous.
It's hygroscopic.
It's unstable (with certain compounds).
It can't be used in colour comps., other than yellow, because it's so intense.

Good BP is far safer and inordinently more versatile than O3.

[Richard H]

Exactly my point! Some people will never get the message until body parts start flying off.

[Rhodri]

Let's hope that never, ever happens.