Ammonium iodate

Ammonium iodate is an inorganic salt which is sparingly soluble in cold, and moderately soluble in hot water, like all iodate salts, it is a strong oxidizer.

Preparation
Ammonium iodate can be obtained by neutralising a solution of iodic acid with ammonia.


 * HIO3 + NH3 → NH4IO3

Using its low solubility in water, it can also be precipitated from an iodate solution with an ammonium salt.


 * 2 KIO3 + (NH4)2SO4 → 2 NH4IO3 + K2SO4

Unlike other iodates, ammonium iodate can't be prepared by dissolving iodine in an ammonium hydroxide solution, instead the highly explosive nitrogen triiodide is formed.


 * 3 I2 + 5 NH3 → 3 NH4I + NH3·NI3

Chemical properties
Because ammonium iodate consists of the reducing ammonium ion and the oxidizing iodate ion, it already starts to decompose at 150 °C into nitrogen, oxygen, iodine and water.


 * NH4IO3 → $1⁄2$N2 + $1⁄2$O2 + $1⁄2$I2 + 2H2O

Below 60 °C this reaction cannot sustain itself, but with catalysts like potassium dichromate or copper(II) chloride it can also combust at room temperature.

Safety
Like all iodates, ammonium iodate is a strong oxidizer and should therefore be kept away from flammable materials like sulfur, phosphorus and metals powders