Periodic acid
Structural formula | ||||||||||||||||
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General | ||||||||||||||||
Surname | Periodic acid | |||||||||||||||
other names |
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Molecular formula | H 5 IO 6 | |||||||||||||||
Brief description |
colorless, almost odorless solid |
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properties | ||||||||||||||||
Molar mass | 227.95 g mol −1 | |||||||||||||||
Physical state |
firmly |
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Melting point |
122 ° C |
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boiling point |
Decomposes at 130-140 ° C |
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solubility | ||||||||||||||||
safety instructions | ||||||||||||||||
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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.
When heated in vacuo, triperiodic acid (H 7 I 3 O 14 ) and meta-periodic acid ((HIO 4 ) n ) are formed through condensation .
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.
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.