Nomenclature
CAS number: 10450-60-9
H
5IO
6; mol wt 227.94.
H 2.21%, I 55.67%, O 42.11%.
Description and references
Prepd by electrolytic oxidation of iodic acid
or from barium periodate and nitric acid: Willard, Inorg. Synth. 1, 172 (1939).
Chemistry of periodic acid and periodates: H. Siebert, Fortschr. Chem. Forsch. 8, 470
(1967). Periodic acid and periodates in organic and bioorganic chemistry:
A. J. Fatiadi, Synthesis 1974, 229. Book: G. Dryhurst, Periodate
Oxidation of Diol and Other Functional Groups (Pergamon
Press, New York, 1970).
Properties
Monoclinic, hygroscopic crystals. mp 122°; dec 130-140° forming I2O5, H2O, and O2. Freely
sol in water. A 38% w/w soln had d417 1.3875. Sol in alcohol, slightly
in ether. Soly in nitric acid (d 1.42) at 26° = 7.82 g/100 ml. When aq solns are evapd
at room temp the “ortho” acid H5IO6 crystallizes
out. If this is heated in a vacuum at 100° and 12 mm it loses water
and is converted to the “meta” acid HIO4, an intermediate
H4I2O9 being formed at 80°. Periodic
acid is a dibasic acid, much weaker than perchloric acid. K1 at 25° = 2.3 × 10-2; K2 = 2 × 10-6. Very easily reduced to iodic acid by nitrous or sulfurous acids
and even by hydrochloric and sulfuric acids. Oxidizes organic material.Use
In organic synthesis. Oxidizer. Determination
of manganese.