An iodate is the polyatomic anion with the formula . It is the most common form of

iodine Iodine is a chemical element with the Symbol (chemistry), symbol I and atomic number 53. The heaviest of the stable halogens, it exists as a semi-lustrous, non-metallic solid at standard conditions that melts to form a deep violet liquid at , ...

in nature, as it comprises the major iodine-containing ores. Iodate

salts In chemistry, a salt is a chemical compound consisting of an ionic assembly of positively charged cations and negatively charged anions, which results in a compound with no net electric charge. A common example is table salt, with positively c ...

are often colorless. They are the salts of iodic acid.

Structure

Iodate is pyramidal in structure. The O–I–O angles range from 97° to 105°, somewhat smaller than the O–Cl–O angles in chlorate.

Reactions

Redox

Iodate is one of several

oxyanion An oxyanion, or oxoanion, is an ion with the generic formula (where A represents a chemical element and O represents an oxygen atom). Oxyanions are formed by a large majority of the chemical elements. The formulae of simple oxyanions are determine ...

s of iodine, and has an

oxidation number In chemistry, the oxidation state, or oxidation number, is the hypothetical charge of an atom if all of its bonds to different atoms were fully ionic. It describes the degree of oxidation (loss of electrons) of an atom in a chemical compound. C ...

of +5. It participates in several redox reactions, such as the

iodine clock reaction The iodine clock reaction is a classical chemical clock demonstration experiment to display chemical kinetics in action; it was discovered by Hans Heinrich Landolt in 1886. The iodine clock reaction exists in several variations, which each involve ...

. Iodate show no tendency to disproportionate to periodate and iodide, in contrast to the situation for chlorate. Iodate is reduced by

sulfite Sulfites or sulphites are compounds that contain the sulfite ion (or the sulfate(IV) ion, from its correct systematic name), . The sulfite ion is the conjugate base of bisulfite. Although its acid ( sulfurous acid) is elusive, its salts are w ...

: :6HSO3- + 2IO3- -> 2I- + 6HSO4- Iodate oxidizes

iodide An iodide ion is the ion I−. Compounds with iodine in formal oxidation state −1 are called iodides. In everyday life, iodide is most commonly encountered as a component of iodized salt, which many governments mandate. Worldwide, iodine de ...

: :5I- + IO3- + 3H2SO4 -> 3I2 + 3H2O + 3SO4^2- Similarly,

chlorate The chlorate anion has the formula ClO3-. In this case, the chlorine atom is in the +5 oxidation state. "Chlorate" can also refer to chemical compounds containing this anion; chlorates are the salts of chloric acid. "Chlorate", when followed by ...

oxidizes iodide to iodate: :I- + ClO3- -> Cl- + IO3- Iodate is also obtained by reducing a

periodate Periodate 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 ...

with a

sulfide Sulfide (British English also sulphide) is an inorganic anion of sulfur with the chemical formula S2− or a compound containing one or more S2− ions. Solutions of sulfide salts are corrosive. ''Sulfide'' also refers to chemical compounds la ...

. The byproduct of the reaction is a

sulfoxide In organic chemistry, a sulfoxide, also called a sulphoxide, is an organosulfur compound containing a sulfinyl () functional group attached to two carbon atoms. It is a polar functional group. Sulfoxides are oxidized derivatives of sulfides. E ...

Acid-base

Iodate is unusual in that it forms a strong hydrogen bond with its parent acid: : IO3- + HIO3 -> H(IO3)2- The anion is referred to as biiodate.

Principal compounds

* Calcium iodate, Ca(IO₃)₂, is the principal ore of iodine. It is also used as a nutritional supplement for cattle. *

Potassium iodate Potassium iodate ( K I O3) is an ionic chemical compound consisting of K+ ions and IO3− ions in a 1:1 ratio. Preparation and properties Potassium iodate is an oxidizing agent and as such it can cause fires if in contact with combustible mater ...

, KIO₃, like

potassium iodide Potassium iodide is a chemical compound, medication, and dietary supplement. It is a medication used for treating hyperthyroidism, in radiation emergencies, and for protecting the thyroid gland when certain types of radiopharmaceuticals are u ...

, has been issued as a

prophylaxis Preventive healthcare, or prophylaxis, consists of measures taken for the purposes of disease prevention.Hugh R. Leavell and E. Gurney Clark as "the science and art of preventing disease, prolonging life, and promoting physical and mental hea ...

against radioiodine absorption in some countries. * Potassium hydrogen iodate (or potassium biiodate), KH(IO₃)₂, is a double salt of potassium iodate and iodic acid and an

acid In computer science, ACID ( atomicity, consistency, isolation, durability) is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of databases, a se ...

as well.

Natural occurrence

Minerals containing iodate are found in the caliche deposits of Chile. The most important iodate minerals are lautarite and brüggenite, but also copper-bearing iodates such as salesite are known.

References

{{reflist Halates