- The higher polyiodides were formed upon crystallization of solutions containing various concentrations of I " and I 2.
- In the solid states, the polyiodides can interact with each other to form chains, rings, or even complicated two-dimensional and three-dimensional networks.
- The polyiodides can be made by addition of stoichiometric amounts of I 2 to solutions containing I " and, with the presence of large KI when a stoichiometric amount of I 2 is added and cooled.
- Discrete polyiodides usually have a linear sequence of iodine atoms and iodide ions, and are described in terms of association between I 2, I " and units, which reflects the origin of the polyiodide.
- Elemental iodine is slightly soluble in water, with one gram dissolving in 3450 ml at 20 癈 and 1280 ml at 50 癈; potassium iodide may be added to increase solubility via formation of triiodide ions, among other polyiodides.