Iodine lipid enveloped viruses. Iodine probably attacks surface proteins of enveloped viruses, and it may also destabilise membrane fatty acids by reacting with unsaturated carbon bonds. In medicine, a saturated solution of potassium iodide is used to treat acute thyrotoxicosis. It is also used to block uptake of iodine-131 in the thyroid gland (see isotopes section above), when this isotope is used as part of radiopharmaceuticals (such as iobenguane) that are not targeted to the thyroid or thyroid-type tissues. Iodine-131 (usually as iodide) is a component of nuclear fallout, and is particularly dangerous owing to the thyroid gland's propensity to concentrate
Iodine the iodyl cation, [IO], and is reduced by concentrated sulfuric acids to iodosyl salts involving [IO]. It may be fluorinated by fluorine, bromine trifluoride, sulfur tetrafluoride, or chloryl fluoride, resulting iodine pentafluoride, which also reacts with iodine pentoxide, giving iodine(V) oxyfluoride, IOF. A few other less stable oxides are known, notably IO and IO; their structures have not been determined, but reasonable guesses are I(IO) and [IO][IO] respectively. More important are the four oxoacids: hypoiodous acid (HIO), iodous acid (HIO), iodic acid (HIO), and periodic acid (HIO or HIO). When iodine dissolves in aqueous solution, the following reactions occur: Hypoiodous