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.

Ammonium Iodate

Ammonium iodate

Ammonium cation
Names
IUPAC name Ammonium iodate
Other names Iodic acid, ammonium salt
Identifiers
CAS Number	13446-09-8 Y
3D model (JSmol)	Interactive image
ChemSpider	145937
ECHA InfoCard	100.033.252
EC Number	236-592-4
PubChem CID	166805
CompTox Dashboard (EPA)	DTXSID60928630
InChI InChI=1S/HIO3.H3N/c2-1(3)4;/h(H,2,3,4);1H3 Key: ZRDJERPXCFOFCP-UHFFFAOYSA-N
SMILES [NH4+].[O-]I(=O)=O
Properties
Chemical formula	NH4IO3
Molar mass	192.94 g/mol
Appearance	white crystalline powder
Density	3.309 g/cm3
Melting point	decomposes at 150 °C
Solubility in water	29.883 g/L (25 °C) [1]
Magnetic susceptibility (χ)	−62.3·10−6 cm3/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Preparation

Ammonium iodate can be obtained by neutralising a solution of iodic acid with ammonia.^[2]

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 → ⁠1/2⁠N₂ + ⁠1/2⁠O₂ + ⁠1/2⁠I₂ + 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.^[2]

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 ^[3]