Iodic acid

IUPAC name	iodic acid
Identifiers
InChI	InChI=InChI=1S/HIO3/c2-1(3)4/h(H,2,3,4)
CAS number	[7782-68-5]
EC number	231-962-1
ChemSpider	22761
Properties
Chemical formula	HIO3
Molar mass	175.91 g mol−1
Appearance	white crystals
Melting point	100 °C decomp.
Acidity (pKa)	0.804
Structure
Molecular geometry	pyramidal; r(I=O) = 181 pm, r(I–OH) = 189 pm, O=I=O = 101.4°, O=I–OH = 97°
Hazards
EU index number	not listed
Flash point	non-flammable
Related compounds
Other anions	Hydriodic acid Periodic acid
Other compounds	Chloric acid Bromic acid
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)

Iodic acid, HIO₃, is a moderately strong oxoacid of iodine. It forms a series of salts called iodates.

Iodic acid may be prepared by the oxidation of suspensions of iodine in water, either by electrolysis or with nitric acid. Unlike chloric and bromic acids, it can be isolated as a white crystalline air-stable solid. The solid decomposes on heating, first to HIO₃·I₂O₅ at about 100 °C, then to iodine pentoxide at about 200 °C.