Sciencemadness Discussion Board

Periodate flash - pink clouds :)

Scalebar - 21-6-2016 at 10:56

I recently came upon a bottle of potassium periodate, out of curiosity I mixed 200mg with 200mg dark aluminum powder. For small bits like that I lay a strip of paper into an iron pan, load the powder and light the opposite end. It took a while to ignite but make a pleasing foof and a cute pink cloud - probably not one for indoor use.

No idea about the stability of such a mix - I only mix flash immediately before use for demos but it makes a nice variation. Next time I might actually try to work out the quantities correctly.

Bert - 21-6-2016 at 19:28

Sounds like you have re-discovered some relative of Hitt's smoke puff formulae from before the second world war- The Wiz will surely have a word or two to add to this.

[Edited on 22-6-2016 by Bert]

Scalebar - 22-6-2016 at 11:31

A mix of 70% iodate - just 400mg total again was considerably more energetic - it lit easily, burnt much more quickly and bordered on a report. The pan even rattled ( it is only thin steel).
I'm not that experienced with perchlorate flash mix - would that have been similarly energetic at such a quantity?

Trying to get my head around the chemistry - presumably I'm getting KI which with the heat gets oxidised to iodine and what? Potassium oxide?

PHILOU Zrealone - 23-6-2016 at 04:52

Quote: Originally posted by Scalebar  
A mix of 70% iodate - just 400mg total again was considerably more energetic - it lit easily, burnt much more quickly and bordered on a report. The pan even rattled ( it is only thin steel).
I'm not that experienced with perchlorate flash mix - would that have been similarly energetic at such a quantity?

Trying to get my head around the chemistry - presumably I'm getting KI which with the heat gets oxidised to iodine and what? Potassium oxide?

Iodate or periodate?

2 KI + 1/2 O2 --> K2O + I2 (migh work upon heating because O2 is more electronegative than I2...remains to see the Delta H°, Delta S and Delta G of reaction to be sure)

About a real testing:
You would need to do several comparative testing with the same granulometry Al, KClO3 (or Na), KBrO3 (or Na), KIO3 (or Na), KClO4 (or Na), KIO4 (or Na).
Same molar ratio mixes.

Then do straw speed burning testing (various diameters) but same lenght.

Then do with same charge weight, same mole number, same volume testing for:
-Sand crushing
-Ballistic pendulum
-Mini Lead block test
-Schrapnell-ising ability on the same kind of copper or iron steel recipient (metal particle size distribution after blast).

Scalebar - 23-6-2016 at 13:04

Oops, yes periodate not iodate.
I'm using saltpetre treated paper now for ignition, 1.5g of 2:1 Al:periodate makes a surprisingly low pitched thump and a smaller flash, no pink or odour of iodine.

I wouldn't be comfortable handling enough to do a lead block test but I am intrigued by this and I might start exploring the other halides, think I need to build a perchlorate cell....