For those worrying about obtaining crystal Iodine because its a DEA listed chemical, I’d like to inform you that it is extremely easy to obtain highly pure I2 crystals with a very simple method.
This is possible using Potassium Iodide (KI), Water, Hydrochloric Acid (HCL), and 3% Hydrogen Peroxide (H2O2).
KI is very cheap, and a useful laboratory chemical to have on hand anyway, as it is used to block radioactive Iodine from getting into the thyroid during a Nuclear incident. Anyway, it is the only thing you’ll need to order, everything else is obtainable over the counter (OTC).
I don’t have molar ratios in front of me, but here is the process. You should read up on stochiometric amounts if you want to be efficient.
Simply dissolve KI into equal mass of H20, add HCL slowly, and then add a smaller amount of the H2O2. The solution will immediately go brown. This is a suspension of I2 crystals. These crystals can be filtered out using any number of filtration methods, coffee filters work fine. The impure I2 can then be added to a beaker, then a round bottom flask/watch glass filled with ice is placed over the beaker, and the beaker placed on a hotplate and gently heated. The I2 crystals will sublimate directly onto the bottom of the rbf giving very pure I2 crystals. Good luck storing them however, the last time I did this I used a smaller RBF and tried to seal it with paraffin wax, and it took about 2 weeks for it to completely my flask.
Either way I2 is very easily obtainable using a number of methods, but this is a very cheap and OTC method to obtain very pure I2, which is useful in many other chemical reactions as well.
Hope this helps someone! my first post here 