Sciencemadness Discussion Board

Crystalline KNO3

tom haggen - 11-3-2004 at 17:13

I took a couple pics of some crystalline KNO3 I have been fooling with. What do you guys think of this pic.

Imga0139.jpg - 76kB


axehandle - 11-3-2004 at 17:19

How did you grow them?

tom haggen - 11-3-2004 at 17:31

I didn't really grow them. I just extracted them from some smoke bombs and just let them cool in that dish and got a really cool crystal formation. I figured I would post the pic.

Haggis - 11-3-2004 at 18:03

Looks like they're still a bit wet. Let me guess: you let it evaporate slowly. I've found that heating crystals don't get that nice of structure.

Does your camera have a macro mode? I like to use that when I'm taking closeups of something that I want detail in. It makes it look nice.

This is a picture of some picrates being formed that I took using macro mode.

102_0285.JPG - 123kB

T_FLeX - 11-3-2004 at 19:04

Thats pretty cool man, never seen kno3 crystals that long. The other day I made some cool looking epson salt crystals almost as long, whish I had taken some pics.


chloric1 - 11-3-2004 at 19:37

Actually, I had a few ml of 35% HNO3 left over from preparing silver nitrate from coin blanks. So instead of polluting, I neutralized it with potassium carbonate because I could. After it stopped fizzing it was about 60 degrees C. I let this set outside for a few minutes(0 degrees) and when it cooled I had lots of pretty long shards! Also, if you can get 35% perchloric acid put some roofing nails in it and wait three days. Filter and pour the blue green liquid into a large shallow dish in a warm place protected from settling dust. You should end up with some blue green ferrous perchlorate in long beautiful needles!

P.S. Most perchlorates crystalize in needle shaped crystals if the salt is sufficiently water soluble.

[Edited on 3/12/2004 by chloric1]

[Edited on 3/12/2004 by chloric1]

tom haggen - 11-3-2004 at 21:02

haggis, I'm not sure if I have a macro mode. is macro mode kind of like a manual focus option? I was just messing around with the manual focus option on my camera and it seems to be working much better for close ups. your pic looks extremely clear. chloric i don't really have any perchloric acid handy, though it would be nice if I did.

[Edited on 12-3-2004 by tom haggen]

BromicAcid - 11-3-2004 at 21:08

Back in high school we took KClO3 and added it to water till a considerable amount dissolved. Then we heated with a bunsen burner (it was in a large test tube) till it all dissolved and waited, after a bit a rainbow of crystals came out of solution, it was incredibly stunning to watch.

Also with KClO3 we took a bit and melted it in a large test tube over a bunsen burner, then dropped in a gummy bear, it bounced all around and shot up purple flames, it was called "The Gummy Bear Goes to Hell" ahhh I think I'll do that one again next week....

tom haggen - 11-3-2004 at 21:22

Some of my first experiences with crystallization was with KCLO3. I found that its much easier to get the crystals to form than it is with nirtate salts. nitrates stay molten very easily. I haven't really worked with molten KCLO3, that gummy bear trick sounds cool. I think i might try it.

[Edited on 12-3-2004 by tom haggen]

Perchloric acid

chloric1 - 23-3-2004 at 10:29

It took me years to get perchloric acid. Until I was able to buy it, I made it. If you are in fact in the US you can buy ammonium perchlorate from pyro suppliers. It runs $10 per pound but more than worthit! If you make aqua regia with nitric and hydrochloric acids, you dissolve the AP crystals and let them sit for about 24 hours. Once reaction commences, leave it alone! It is safest to keep this mixture cool until the ruby-brown color disappears. Once it achieves a clear yellow this signifies that the ammonium ion in decomposed completely. Now cautiously heat the mixture and distill off the HCL, chlorine, and Nitric acid. Excellent ventalation is imperitive! Do this until no more smokey fumes come off. This will be your crude HClO4!! I hope this helps!:D

[Edited on 3/23/2004 by chloric1]

chemoleo - 23-3-2004 at 12:51

Great idea!
Sadly though, it still contains other acids :(
Plus, if you start off with KClO4 instead, it's even harder to get salt-free HClO4..
But that's off topic I know. Maybe I should have a look at the perchloric acid thread again!

Saerynide - 23-3-2004 at 14:04

Could you electrolyze a solution of ammonium perchlorate? Or use a salt bridge for a metal perchlorate salt?

hodges - 23-3-2004 at 15:20

I wouldn't want to electorlyze anything that had both ammonia and chlorine in it for fear of creating nitrogen trichloride. In theory, electrolyzing a solution of potassium perchlorate should work. Subject to the usual difficulties when trying to produce an acid by electrolysis.

Theoretic - 24-3-2004 at 02:20

On the topic of obtaining HClO4 via AP and aqua regia... If the ammonium ion is decomposed by chlorine from aqua regia (due to the equilibrium 3HCl + HNO3 <=> NOCl + Cl2 + 2H2O), then either nitrogen evolves and hydrogen chloride is made (plus NOCl from the shifted equilibrium, which is chemically reactive and does mess up your final product but is volatile and can be distilled off), or, alternatively, nitrogen trichloride is made (with excess chorine), which can (and often does) explode! It can decompose to nitrogen and chlorine safely, but this still wastes aqua regia.
An alternative is to add ferric chloride to your AP solution to form NH4Cl and ferric perchlorate, dry it out and heat cautiously untill all the ammonium chloride distills away, then put it into hot water and dilute untill it hydrolyses and Fe(OH)3 precipitates, filter and you're there (or so I hope)!

chloric1 - 24-3-2004 at 19:55

Yes Theoretic i like your metal salt hydrolysis but it really would be hard removing the iron. Yes you are right about a potential explosion hazard! That is why perchlorate manufacturers abandoned the batch process but if you keep the quanties under 500ml you ahve reduced risk. And remeber what I said about the red color in the last post! Dont heat it ,throw it against brick walls,add other chemicals or expose to direct sunlight! Just let it chill out for about 24 to 48 hours and the oxidizers in solution will take care of your ammonium ion for you. Just rember clear yellow is all is safe and clear and red is for danger!:o:o