IODIDE by vulcanel~
It's a good question.
Most elements don't occur alone in their elemental forms in nature, but rather are combined with others, common exceptions being gold, silver, copper, Elements in the first two columns on the left of the periodic table are metals, including sodium, potassium, rubidium, cesium, lihium, magnesium, calcium, strontium. But these are active metals, they like to give away an negatively charged electron and in so doing, themselves become positive ions, and are called "cations" . Meeeeoooooowww. (insert Cat Scratch Fever video here)
Elements of the halogen family in the penultimate right column on the other side of the periodic table, such as individual iodine atoms, are deficient in electrons and want to absorb one. When they absorb one, they become negatively charged ions, and are called "anions". They are so lonely, they will even pair up with one another and share some of their electrons, just so they can each have more electrons. This is why fluorine, chlorine, bromine and iodine exist as diatomic molecules, with two atoms comprising each molecule.
Now to answer the question.
There are two common forms of iodine. One is diatomic iodine, with two atoms comprising an I2 molecule. The other form is iodide anion, which has received an electron from another atom in the world. It could be a potassium atom. If you put potassium and iodine together, the potassium will give its electron to iodine and form a positively-charged potassium cation and a negatively-charged iodide anion, and you will have potassium iodide. When you do this, sparks fly, and I mean literally. Sodium chloride, which is table salt , is analogous.
Iodine exists in another form, which is called tri-iodide anion. This is made by combining one iodide anion with one diatomic iodine molecule. The resulting anion carries a single negative charge and has three iodine atoms attached to one another in substantially linear configuration. To balance the charge, a cation must be present, such as potassium.
When Lugol's is made, an aqueous soluiton of potassium iodide (LI) is prepared by dissolving KI in water, say ten grams KI in 85 grams water. Then, once dissolved, five grams of iodine crystals are added to the potassium iodide solution. The diatomic iodine adds to the iodide ions in the KI solution to form potassium tri-iodide, which is what Lugol's solution REALLY is.
Tri-iodide is stable, but when diluted it disproportionates back to iodide ions and elemental iodine. So, by ingesting diluted Lugol's iodine, a test subject will be provided with both iodied and elemental iodine.
The elemental iodine itself can react with water to form hydriodic acid and hypoiodous acid, and with potassium present there will be a complex mixture present, but one need not be too concerned with the equilibria associated with these. Suffice it, that Lugol's solution is REALLY a solution of potassium tri-iodide, which contains both iodide ions and elemental iodine, in a married form.
Studies have shown that elemental iodine seems to have benefits that iodide alone does not, I believe it was Ghent and Hill, while working in the Mimetix study.