Sodium periodate is an inorganic salt, composed of a

sodium Sodium is a chemical element with the symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable iso ...

cation An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convent ...

and the periodate

anion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convent ...

. It may also be regarded as the sodium

salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quantitie ...

of periodic acid. Like many periodates, it can exist in two different forms: sodium ''meta''periodate (formula‍ NaIO₄) and sodium ''ortho''periodate (normally Na₂H₃IO₆, but sometimes the fully reacted salt Na₅IO₆). Both salts are useful oxidising agents.

Preparation

Classically, periodate was most commonly produced in the form of sodium hydrogen periodate (). This is commercially available, but can also be produced by the oxidation of iodates with

chlorine Chlorine is a chemical element with the Symbol (chemistry), symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate betwee ...

and

sodium hydroxide Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula NaOH. It is a white solid ionic compound consisting of sodium cations and hydroxide anions . Sodium hydroxide is a highly caustic base and alkali ...

. Or, similarly, from iodides by oxidation with

bromine Bromine is a chemical element with the symbol Br and atomic number 35. It is the third-lightest element in group 17 of the periodic table (halogens) and is a volatile red-brown liquid at room temperature that evaporates readily to form a simila ...

and sodium hydroxide: :\overset + Cl2 + 4 NaOH -> Na3H2IO6 + 2NaCl + H2O :NaI + 4 Br2 + 10 NaOH -> Na3H2IO6 + 8 NaBr + 4 H2O Modern industrial scale production involves the electrochemical oxidation of iodates, on a

lead dioxide Lead(IV) oxide is the inorganic compound with the formula PbO2. It is an oxide where lead is in an oxidation state of +4. It is a dark-brown solid which is insoluble in water. It exists in two crystalline forms. It has several important applicatio ...

() anode, with the following standard electrode potential: :H5IO6 + H+ + 2e- -> IO3- + 3 H2O Sodium metaperiodate can be prepared by the dehydration of sodium hydrogen periodate with

nitric acid Nitric acid is the inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but older samples tend to be yellow cast due to decomposition into oxides of nitrogen. Most commercially available nitri ...

. :Na3H2IO6 + 2 HNO3 -> NaIO4 + 2 NaNO3 + 2 H2O

Structure

Sodium metaperiodate (NaIO₄) forms tetragonal crystals ( space group ''I''4₁/_a) consisting of slightly distorted ions with average I–O bond distances of 1.775 Å; the Na⁺ ions are surrounded by 8 oxygen atoms at distances of 2.54 and 2.60 Å. Sodium hydrogen periodate (Na₂H₃IO₆) forms

orthorhombic In crystallography, the orthorhombic crystal system is one of the 7 crystal systems. Orthorhombic lattices result from stretching a cubic lattice along two of its orthogonal pairs by two different factors, resulting in a rectangular prism with a r ...

crystals (space group Pnnm). Iodine and sodium atoms are both surrounded by an octahedral arrangement of 6 oxygen atoms; however the NaO₆ octahedron is strongly distorted. IO₆ and NaO₆ groups are linked via common vertices and edges. Powder diffraction indicates that Na₅IO₆ crystallises in the

monoclinic In crystallography, the monoclinic crystal system is one of the seven crystal systems. A crystal system is described by three vectors. In the monoclinic system, the crystal is described by vectors of unequal lengths, as in the orthorhombic s ...

system (space group C2/m).

Uses

Sodium periodate can be used in solution to open saccharide rings between

vicinal diols Vicinal may refer to: * Vicinal (chemistry), stands for any two functional groups bonded to two adjacent atoms. * Vicinal (logology), a word where all letters have alphabetic neighbors. * Vicinal tramway or ''Buurtspoor'', a system of narrow gauge ...

leaving two aldehyde groups. This process is often used in labeling saccharides with fluorescent molecules or other tags such as

biotin Biotin (or vitamin B7) is one of the B vitamins. It is involved in a wide range of metabolic processes, both in humans and in other organisms, primarily related to the utilization of fats, carbohydrates, and amino acids. The name ''biotin'', bor ...

. Because the process requires vicinal diols, periodate oxidation is often used to selectively label the 3′-ends of

RNA Ribonucleic acid (RNA) is a polymeric molecule essential in various biological roles in coding, decoding, regulation and expression of genes. RNA and deoxyribonucleic acid ( DNA) are nucleic acids. Along with lipids, proteins, and carbohydra ...

(

ribose Ribose is a simple sugar and carbohydrate with molecular formula C5H10O5 and the linear-form composition H−(C=O)−(CHOH)4−H. The naturally-occurring form, , is a component of the ribonucleotides from which RNA is built, and so this compo ...

has vicinal diols) instead of DNA as deoxyribose does not have vicinal diols. NaIO₄ is used in

organic chemistry Organic chemistry is a subdiscipline within chemistry involving the scientific study of the structure, properties, and reactions of organic compounds and organic materials, i.e., matter in its various forms that contain carbon atoms.Clayden, J.; ...

to cleave

diol A diol is a chemical compound containing two hydroxyl groups ( groups). An aliphatic diol is also called a glycol. This pairing of functional groups is pervasive, and many subcategories have been identified. The most common industrial diol is e ...

s to produce two

aldehyde In organic chemistry, an aldehyde () is an organic compound containing a functional group with the structure . The functional group itself (without the "R" side chain) can be referred to as an aldehyde but can also be classified as a formyl grou ...

In 2013 the

US Army The United States Army (USA) is the land service branch of the United States Armed Forces. It is one of the eight U.S. uniformed services, and is designated as the Army of the United States in the U.S. Constitution.Article II, section 2, cla ...

announced that it would replace environmentally harmful chemicals barium nitrate and

potassium perchlorate Potassium perchlorate is the inorganic salt with the chemical formula K Cl O4. Like other perchlorates, this salt is a strong oxidizer although it usually reacts very slowly with organic substances. This, usually obtained as a colorless, crysta ...

with sodium metaperiodate for use in their tracer ammunition.

References

*See Fatiadi, ''Synthesis'' (1974) 229–272 for a review of periodate chemistry. {{DEFAULTSORT:Sodium Periodate Periodates Sodium compounds Oxidizing agents

Preparation

Structure

Uses

See also

References