Calcium Oxyiodide, CaI₂.3CaO.16H₂O

A crystalline compound, CaI₂.3CaO.16H₂O, has been prepared. It is decomposed by water and alcohol, but is stable at 25° C. in contact with a solution containing from 28.44 per cent, to 66.68 per cent, of calcium iodide. It assumes a red-violet colour under the influence of light, is less hygroscopic than the neutral iodide, and on heating it is probably dehydrated with the separation of iodine. In vacuo, at ordinary temperatures, water is removed and the tri-hydrate, CaI₂.3CaO.3H₂O, less unstable to light but very hygroscopic, is obtained.