Iodic acid

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Iodic acid
Iodic acid
Ball-and-stick model of iodic acid
Ball-and-stick model of iodic acid
Space-filling model of iodic acid
Space-filling model of iodic acid
Names
Other names
Iodic(V) acid
Identifiers
3D model (
JSmol
)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard
 100.029.056 Edit this at Wikidata
UNII
  • InChI=1S/HIO3/c2-1(3)4/h(H,2,3,4) checkY
    Key: ICIWUVCWSCSTAQ-UHFFFAOYSA-N checkY
  • InChI=1/HIO3/c2-1(3)4/h(H,2,3,4)
    Key: ICIWUVCWSCSTAQ-UHFFFAOYAT
  • O[I+2]([O-])[O-]
Properties
HIO3
Molar mass 175.91 g/mol
Appearance White solid
Density 4.62 g/cm3, solid
Melting point 110 °C (230 °F; 383 K)
269 g/100 mL (20 °C)
Acidity (pKa) 0.75
Conjugate base
 Iodate
−48.0·10−6 cm3/mol
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
 acid, corrosive, oxidant
GHS labelling:[1]
GHS03: OxidizingGHS05: Corrosive
Danger
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasFlammability 0: Will not burn. E.g. waterInstability 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g. calciumSpecial hazard OX: Oxidizer. E.g. potassium perchlorate
3
0
1
OX
Flash point Non-flammable
Related compounds
Other cations
 Lithium iodate
Potassium iodate
Related
oxoacids
 Chloric acid
Bromic acid
Related compounds
 Hydroiodic acid
Iodine pentoxide
Periodic acid
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)

Iodic acid is a white water-soluble solid with the

halogens. When heated, samples dehydrate to give iodine pentoxide
. On further heating, the iodine pentoxide further decomposes, giving a mix of iodine, oxygen and lower oxides of iodine.

Preparation

Iodic acid can be produced by

oxidizing iodine I2 with strong oxidizers such as nitric acid HNO3, chlorine Cl2, chloric acid HClO3 or hydrogen peroxide H2O2,[2]
for example:

Iodic acid is also produced by the reaction of iodine monochloride with water:

Structure

Iodic acid crystallises from acidic solution as

hydrogen bonding and intermolecular iodine-oxygen interactions. The I=O bond lengths are 1.81 Å while the I–OH distance is 1.89 Å.[3][4][5] Several other polymorphs have been reported, including an orthorhombic γ form in space group Pbca[6] and an orthorhombic δ form in space group P212121.[7]
All of the polymorphs contain pyramidal molecules, hydrogen bonding and I···O interactions, but differ in packing arrangement.

Properties

Iodic acid is a relatively

oxidizing in acidic solution, less so in basic solution. When iodic acid acts as oxidizer, then the product of the reaction is either iodine, or iodide ion. Under some special conditions (very low pH and high concentration of chloride ions, such as in concentrated hydrochloric acid), iodic acid is reduced to iodine trichloride, a golden yellow compound in solution and no further reduction occurs. In the absence of chloride ions, when there is an excess amount of reductant, then all iodate is converted to iodide ion. When there is an excess amount of iodate, then part of the iodate is converted to iodine.[citation needed
] It may be used in preparation of ionization to form alkyl halides.

Uses

Iodic acid is used as a

strong bases, using methyl red or methyl orange as the indicator
.

Use in salt industry

Iodic acid can be used to synthesize sodium or potassium iodate for increasing iodine content of salt.[citation needed]

Other oxyacids

Iodate is part of a series of oxyacids in which iodine can assume oxidation states of −1, +1, +3, +5, or +7. A number of neutral iodine oxides are also known.

Iodine oxidation state −1 +1 +3 +5 +7
Name Hydrogen iodide Hypoiodous acid
Iodous acid
 Iodic acid Periodic acid
Formula HI HIO HIO2 HIO3 HIO4 or H5IO6

References

  1. ^ "Iodic acid" (PDF).
  2. ISBN 978-3-11-017770-1.{{cite book}}: CS1 maint: location missing publisher (link
    )
  3. ISBN 978-0-08-037941-8
    .
  4. doi:10.1021/ja01846a068
    .
  5. doi:10.3891/acta.chem.scand.46-1146
    .
  6. doi:10.1002/zaac.200500099
    .
  7. S2CID 104100313
    .
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