AbstractThe volatility of iodine above dilute CsI solutions has been investigated experimentally. The partitioning of iodine between air and solutions prepared with iodide was found to increase with decreasingpH and iodide concentration. Aqueous to gaseous partition coefficients ranging from 3 X 103to 107were observed indicating that only a very small fraction of the iodide was oxidized to volatile forms. It was concluded that under these very dilute conditions, the rate of iodide oxidation was proportional to the square root of the iodide concentration; the rate also depended onpH under acidic conditions but not under basic conditions.