Periodates

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Structure of the metaperiodate anion

Periodates are the salts of various periodic acids ; Depending on the acid, a distinction is made between orthoperiod data (IO 6 5− ), metaperiod data (IO 4 - ), dimesoperiod data (I 2 O 9 4− ) and mesoperiod data (IO 5 3− ).

presentation

Periodates can be prepared from iodates by electrochemical oxidation ; here the anode consists of lead dioxide . Periodate is also formed when iodates are oxidized with chlorine . In an alkaline solution at temperatures around 100 ° C, iodates and chlorine or hypochlorite form acidic salts of the form M 5-n H n IO 6 (with n = 2.3).

properties

Orthoperiodates are only sparingly soluble in water, with hydrolysis occurring; the salts decompose when heated. Periodates are powerful oxidizing agents . In contrast to perchlorates and perbromates , the reactions of which are often kinetically inhibited and require a considerable activation energy despite sufficient oxidizing power, the reactions with periodates are relatively fast.

use

Periodates are used in organic chemistry as oxidizing agents that can cleave CC bonds; Here, sodium metaperiodate (NaIO 4 ) is mainly used for glycol cleavage ( Malaprade reaction ) and for the preparation of deoxyribonucleotides . Periodates are also highly selective etchants for certain ruthenium- containing oxides.

Examples

Individual evidence

  1. ↑ a b c d Entry on periodates. In: Römpp Online . Georg Thieme Verlag, accessed on April 3, 2012.
  2. ^ Wissenschaft-Online-Lexika: Entry on "Periodic Acid" in the Lexikon der Chemie, accessed on April 3, 2012.
  3. ↑ Constantinos E. Efstathiou, Themistocles P. Hadjiioannou: Analytical and other Applications of Periodate-sensitive Electrodes . In: Reviews in Analytical Chemistry . 2011, 14: pp. 253-277, doi : 10.1515 / REVAC.1995.14.4.253 .
  4. ↑ Dieter Weber, Róza Vöfély, Yuehua Chen, Yulia Mourzina, Ulrich Poppe: Variable resistor made by repeated steps of epitaxial deposition and lithographic structuring of oxide layers by using wet chemical etchants . In: Thin Solid Films. 533, 2013, pp. 43-47, doi : 10.1016 / j.tsf.2012.11.118 .