Na 3 H 2 IO 6 + 2 HNO 3 ⟶ NaIO 4 + 2 NaNO 3 + 2 H 2 O {\displaystyle {\ce {Na3H2IO6 + 2 HNO3 -> NaIO4 + 2 NaNO3 + 2 H2O}}} H 5 IO 6 ⟶ HIO 4 + 2 H 2 O {\displaystyle {\ce {H5IO6 -> HIO4 + 2 H2O}}} Periodate can exist in a variety of forms in aqueous media, with pH being a controlling factor. Orthoperiodate has a number of acid dissociation constants. [5] [6] H 5 IO 6 ↽ − − ⇀ H 4 IO 6 − + H + {\displaystyle {\ce {H5IO6 <=> H4IO6- + H+}}} p K a = 3.29 H 4 IO 6 − ↽ − − ⇀ H 3 IO 6 2 − + H + {\displaystyle {\ce {H4IO6- <=> H3IO6 Periodate / p ə ˈ r aɪ . ə d eɪ t/ is an anion composed of iodine and oxygen. It is one of a number of oxyanions of iodine and is the highest in the series, with iodine existing in oxidation state +7. Unlike other perhalogenates, such as perchlorate, it can exist in two forms: metaperiodate IO − Classically, periodate was most commonly produced in the form of sodium hydrogen periodate ( Na 3H 2IO 6). [2] This is commercially available, but can also be produced by the oxidation of iodates with chlorine and sodium hydroxide. [3] Or, similarly, from iodides by oxidation with bromine and sodium hydroxide: Record of Natriumperiodat in the GESTIS Substance Database of the Institute for Occupational Safety and Health, accessed on 2018-01-08.

H 5 IO 6 + H + + 2 e − ⟶ IO 3 − + 3 H 2 O {\displaystyle {\ce {H5IO6 + H+ + 2e- -> IO3- + 3 H2O}}} E° = 1.6 V [5] Classically, periodate was most commonly produced in the form of sodium hydrogen periodate ( Na 3H 2IO 6). [3] This is commercially available, but can also be produced by the oxidation of iodates with chlorine and sodium hydroxide. [4] Or, similarly, from iodides by oxidation with bromine and sodium hydroxide: NaIO 3 + NaOCl sodium hypochlorite ⟶ NaIO 4 + NaCl {\displaystyle {\ce {NaIO3{}+{\overset {sodium\ hypochlorite}{NaOCl}}->NaIO4{}+NaCl}}} Forms and interconversion [ edit ] Periodates were discovered by Heinrich Gustav Magnus and C. F. Ammermüller; who first synthesised periodic acid in 1833. [1] Synthesis [ edit ] Hill, Arthur E. (October 1928). "Ternary Systems. VII. The Periodates of the Alkali Metals". Journal of the American Chemical Society. 50 (10): 2678–2692. doi: 10.1021/ja01397a013.Betz, T.; Hoppe, R. (May 1984). "Über Perrhenate. 2. Zur Kenntnis von Li 5ReO 6 und Na 5ReO 6 – mit einer Bemerkung über Na 5IO 6". Zeitschrift für anorganische und allgemeine Chemie (in German). 512 (5): 19–33. doi: 10.1002/zaac.19845120504. In this regard it is comparable to the tellurate ion from the adjacent group. It can combine with a number of counter ions to form periodates, which may also be regarded as the salts of periodic acid.

Andrew G. Wee, Jason Slobodian, Manuel A. Fernández-Rodríguez and Enrique Aguilar "Sodium Periodate" e-EROS Encyclopedia of Reagents for Organic Synthesis 2006. doi: 10.1002/047084289X.rs095.pub2 Sodium metaperiodate (NaIO 4) forms tetragonal crystals ( space group I4 1/ a) consisting of slightly distorted IO − Sodium metaperiodate can be prepared by the dehydration of sodium hydrogen periodate with nitric acid. [3] Na 3 H 2 IO 6 + 2 HNO 3 ⟶ NaIO 4 + 2 NaNO 3 + 2 H 2 O {\displaystyle {\ce {Na3H2IO6 + 2 HNO3 -> NaIO4 + 2 NaNO3 + 2 H2O}}} Structure [ edit ] Sodium periodate is an inorganic salt, composed of a sodium cation and the periodate anion. It may also be regarded as the sodium salt of periodic acid. Like many periodates, it can exist in two different forms: sodium metaperiodate (formula‍NaIO 4) and sodium orthoperiodate (normally Na 2H 3IO 6, but sometimes the fully reacted salt Na 5IO 6). Both salts are useful oxidising agents. [2] Preparation [ edit ]

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a b Riley, edited by Georg Brauer; translated by Scripta Technica, Inc. Translation editor Reed F. (1963). Handbook of preparative inorganic chemistry. Volume 1 (2nded.). New York, N.Y.: Academic Press. pp.323–324. ISBN 012126601X. {{ cite book}}: |first= has generic name ( help) CS1 maint: multiple names: authors list ( link) They can also be generated directly from iodates by treatment with other strong oxidizing agents such as hypochlorites: Jansen, Martin; Rehr, Anette (1988). "Na 2H 3IO 6, eine Variante der Markasitstruktur". Zeitschrift für anorganische und allgemeine Chemie (in German). 567 (1): 95–100. doi: 10.1002/zaac.19885670111. Parsons, Roger (1959). Handbook of electrochemical constants. Butterworths Scientific Publications Ltd. p. 71. NaIO 3 sodium iodate + Cl 2 + 4 NaOH ⟶ Na 3 H 2 IO 6 + 2 NaCl + H 2 O {\displaystyle {\ce {{\overset {sodium\ iodate}{NaIO3}}+Cl2{}+4NaOH->Na3H2IO6{}+2NaCl{}+H2O}}} NaI + 4 Br 2 + 10 NaOH ⟶ Na 3 H 2 IO 6 + 8 NaBr + 4 H 2 O {\displaystyle {\ce {NaI + 4 Br2 + 10 NaOH -> Na3H2IO6 + 8 NaBr + 4 H2O}}}