Periodic acid

Structural formula
General
Surname	Periodic acid
other names	Periodic acid; Overiodic acid; Orthoperiodic acid;
Molecular formula	H 5 IO 6
Brief description	colorless, almost odorless solid
External identifiers / databases
EC number	233-937-0
ECHA InfoCard	100.030.839
PubChem	25289
Wikidata	Q411297
properties
Molar mass	227.95 g mol −1
Physical state	firmly
Melting point	122 ° C
boiling point	Decomposes at 130-140 ° C
solubility	very good in water (3000 g l −1 at 20 ° C), ethanol and DMSO ; bad in diethyl ether;
safety instructions
H and P phrases	H: 271-314
	P: 210-221-301 + 330 + 331-305 + 351 + 338-309 + 310
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Periodic acid , also periodic acid , is an acid of the element iodine . Their salts are called periodates and can be used as oxidizing agents, for example in organic syntheses.

properties

As orthoperiodic acid (H ₅ IO ₆ ), the compound is the only iodine (VII) acid which is stable in water.

It is a powerful oxidizing agent and a weak polybasic acid having a pK _s value of 3.29.

Orthoperiodic acid crystallizes in monoclinic form , space group P 2 ₁ / n (space group no. 14, position 2) , with the lattice parameters a = 5.28 Å , b = 18.35 Å, c = 4.95 Å and β = 111.4 °. It has an almost octahedral structure, with the double bond to the oxygen taking up more space and thus indenting a ligand plane. There are angles of less than 90 ° between the ligands. Template: room group / 14.2

When heated in vacuo, triperiodic acid (H ₇ I ₃ O ₁₄ ) and meta-periodic acid ((HIO ₄ ) _n ) are formed through condensation .

Structural formula of triperiodic acid
Structural formula of meta-periodic acid

Manufacturing

Orthoperiodic acid is made from barium orthoperiodate and nitric acid. One makes use of the fact that barium nitrate is insoluble in nitric acid.

{\ displaystyle \ mathrm {Ba_ {3} H_ {4} (IO_ {6}) _ {2} +6 \ HNO_ {3} \ rightleftharpoons \ 2 \ H_ {5} IO_ {6} +3 \ Ba (NO_ {3}) _ {2}}}

use

see PAS response

Individual evidence

↑ ^a ^b ^c ^d ^e ^f Data sheet periodic acid for synthesis (PDF) from Merck , accessed on November 4, 2012.
↑ ^a ^b Entry on periodic acid. In: Römpp Online . Georg Thieme Verlag, accessed on July 14, 2014.
↑ Cotton-Wilkinson: Inorganic Chemistry , 3rd Edition, Verlag Chemie, Weinheim 1974, ISBN 3-527-25503-6 .
↑ YD Feikema: The Crystal Structures of Two oxy-Acids of Iodine. I. A Study of Orthoperiodic Acid, H ₅ IO ₆ , by Neutron Diffraction. In: Acta Crystallographica , 20, 1966, pp. 765-769, doi : 10.1107 / S0365110X66001828 .
↑ G. Brauer (Ed.): Handbook of Preparative Inorganic Chemistry , 2nd ed., Vol. 1, Academic Press 1963, pp. 322-323.

[Merck-1] ↑ ^a ^b ^c ^d ^e ^f Data sheet periodic acid for synthesis (PDF) from Merck , accessed on November 4, 2012.

[roempp-2] Entry on periodic acid. In: Römpp Online . Georg Thieme Verlag, accessed on July 14, 2014.

[3] Cotton-Wilkinson: Inorganic Chemistry , 3rd Edition, Verlag Chemie, Weinheim 1974, ISBN 3-527-25503-6 .

[4] YD Feikema: The Crystal Structures of Two oxy-Acids of Iodine. I. A Study of Orthoperiodic Acid, H ₅ IO ₆ , by Neutron Diffraction. In: Acta Crystallographica , 20, 1966, pp. 765-769, doi : 10.1107 / S0365110X66001828 .

[5] G. Brauer (Ed.): Handbook of Preparative Inorganic Chemistry , 2nd ed., Vol. 1, Academic Press 1963, pp. 322-323.