Iodine oxides are chemical compounds of oxygen and iodine. Iodine has only two stable oxides which are isolatable in bulk, iodine tetroxide and iodine pentoxide, but a number of other oxides are formed in trace quantities or have been hypothesized to exist.The chemistry of these compounds is complicated with only a few having been well characterized. Many have been detected in the atmosphere and are believed to be particularly important in the marine boundary layer. Diiodine pentoxide (I2O5) is the anhydride of iodic acid and the only stable anhydride of an iodine oxoacid.