Ive been watching the lab tips forum for a couple months now and this is my first post so ill try my best :P.

This guy I know has been trying to get Iodine crystals from Iodine Tincture 2% by first putting Muriatic Acid, ~31% HCl until the pH of the liquid was 3 - 4. Then he added 30 mL of purified water then into a pint of H202. Its been sitting there for about 4 hours now and all he said that happened is the liquid is now totally clear and is bubbling. But no visible crystals. SWIM hasnt actually ever seen iodine crystals are they just so clear that they blend in with the clear liquid? Somebody steal em? Any tips? Flames? Thanks.

1 pint of H202 is too much for 2% tinc(unless SWIU happened to have 3 pints 2%).

All of the I2 crystals were over-oxidized and shredded to bits.

Try again with less than 1/2 of that amount of Peroxide.

Lukky D

Lukky thanks for the exceptionally quick reply. SWIM did'nt know using too much H2O2 could screw it up.

If you do a search, you'll find the correct way to do this.

kman - are you serious? omgomg..

lukkydleprachan - I'm back and SWIM tried with 1/2 a bottle of H2O2 3% into 30mL Iodine Tinc 2% /w few drops HCl + 30 mL H2O and noticed some sort of blue crud forming on the bottom of the bottle. After 3 hrs SWIM poured the liquid into another bottle and added a little more H2O2. Then SWIM added a little bit of H2O to the previous bottle and shook it until the blue stuff was off the bottom of the bottle. Then through a bedsheet to try to obtain the crystals. All that was seen was it turning the cloth orange and black in the center. No crystals.

Any ideas Lukky?

Thanks

Swim's never tried the method posted on this board, but there's one on rhodium that swim uses, and it gives as much as the one on here.

There's an artical on this in the KFB look there, that should work.

Understanding the point of the procedur may help one to be more successful.

The first objective is too severely thin the alchohol that is keeping the I2 crystals dissolved. Do this by adding about 2 to 2-1/2 times as much water as tincture(maybe more, SWIL has never really like playing with I2 so he hasn't experimented much with increasing yields, No need). Then the objective is too make the solution highly acidic by adding approximately 1/8th as much HCl as tincture. Overshooting with the HCl shouldn't do a whole lot except increase the necessary final washings. Then add about 1x as much H202 as tincture. Watch the crystals start to grow in the bottom of the jar/beaker/or other non-metallic. If nothing appears to happen, continue to add water to the solution until it begins to clear to the color of "weak tea". At this point, the alky should be thinned enough so that the crystals will precipitate rather than redisolve.

Lukky D

If you want to listen to someone...Listen to Lukky. He is one of the been there, done that kind of guys here. Lukky has earned his stripes for a good reason, not just here either. Thank you Lukky.

*adds to his notebook*

[This message has been edited by LwaysTired (edited 10-05-2003).]