Periodic acid exists as colorless crystals, soluble in water and ethanol but slightly soluble in ether. Upon dehydration, it forms metaperiodic acid (HIO₄). Further dehydration leads to decomposition, ultimately yielding iodine pentoxide (I₂O₅).
In
dilute solution, periodic acid exists as H+ and IO4-.
When more concentrated, orthoperiodic acid, H5IO6, is
formed. Note that this compound is essentially a dihydrate,
HIO4·2H2O. This can be obtained as a crystalline
solid. O-periodic acid can be dehydrated to metaperiodic
acid, m-HIO4. Further heating gives di-iodine pentoxide
(I2O5) and O2. The anhydride di-iodine heptoxide,
i.e. I2O7, does not exist in nature but can be formed
synthetically.
Periodic acid is used as a component for glycoprotein stains. It serves as a pharmaceutical and synthetic intermediate and is used in silk screen printing. It acts as an oxidizing agent especially the cleavage of 1,2 diols to prepare dialdehydes. It has selective oxidation powers which makes it an ideal reagent for the reclamation of silk screens in the printing industry. It finds application in life sciences for the analysis of intracellular polysaccharides like glycogen, starch and cellulose. Furthermore, it is used in the oxidation reactions converting sulfides into sulfones, catalyzed by chromium(VI) oxide and oxidation reactions converting alcohols to aldehydes and ketones.
PERIODIC ACID is used as an oxidiser and in the determination of manganese.
ChEBI: Orthoperiodic acid is an iodine oxoacid. It is a conjugate acid of an orthoperiodate(1-).
A 100 g quantity of Ba₃H₄(IO₆)₂ is moistened with 75 mL of H₂O and treated with 200 mL of colorless nitric acid (HNO₃). The mixture is agitated, heated to 60–70 °C for 1 h, and then cooled to 30–40 °C. The precipitated Ba(NO₃)₂ is filtered off using a glass frit filter. The residue is washed free of periodate by stirring with concentrated HNO₃. The combined filtrate is evaporated at 60–70 °C under aspirator vacuum (if additional Ba(NO₃)₂ precipitates, it is removed by filtration, and evaporation continues) until H₅IO₆ begins to crystallize. After cooling, colorless, glistening crystals of periodic acid (H₅IO₆) form. Due to the tendency of the solution to become supersaturated, prolonged waiting may be required. The crystals are collected by filtration and dried under vacuum at 50 °C. A second crop of crystals may be obtained by further evaporating the mother liquor.
Paraperiodic acid H5IO6, is obtained from sodium paraperiodate, formed by action of chlorine upon a NaOH solution containing I2. On vacuum drying, paraperiodic acid yields metaperiodic acid, HIO4, and dimesoperiodic acid, H4I2O9; which form heteropoly acids with a number of oxides and acids. The periodic acids and their salts are strong oxidizing agents both with inorganic and organic compounds.
Periodic acid (H5IO6) is an oxoacid of iodine. It is commonly used as an oxidizing agent in organic synthesis for the preparation of useful chemical intermediates. Periodic acid is also used in oxidative cleavage reactions.
Flammability and Explosibility
Not classified
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