chemistry Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science that covers the Chemical element, elements that make up matter to the chemical compound, compounds made of atoms, molecules and ions ...

, the perbromate ion is the

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 ...

having the chemical formula . It is an

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 ...

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 ...

, the

conjugate base A conjugate acid, within the Brønsted–Lowry acid–base theory, is a chemical compound formed when an acid donates a proton () to a base—in other words, it is a base with a hydrogen ion added to it, as in the reverse reaction it loses a ...

perbromic acid The compound perbromic acid is the inorganic compound with the formula HBrO4. It is an oxoacid of bromine. Perbromic acid is unstable and cannot be formed by displacement of chlorine from perchloric acid, as periodic acid is prepared; it can only ...

, in which bromine has the

oxidation state 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 ...

+7. Unlike its chlorine () and iodine () analogs, it is difficult to synthesize. It has

tetrahedral molecular geometry In a tetrahedral molecular geometry, a central atom is located at the center with four substituents that are located at the corners of a tetrahedron. The bond angles are cos−1(−) = 109.4712206...° ≈ 109.5° when all four substituents are ...

. The term perbromate also refers to a compound that contains the anion or the

functional group In organic chemistry, a functional group is a substituent or moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions regardless of the rest ...

. The perbromate ion is a strong oxidizing agent. The reduction potential for the / Br⁻ couple is +0.68 V at pH 14. This is comparable to

selenite Selenite may refer to: Substances containing selenium *A selenium-containing anion or ionic compound with the SeO32− anion: **Selenite (ion), anion is a selenium oxoanion with the chemical formula SeO32− ***Selenous acid, the conjugate acid, w ...

's reduction potential.

Synthesis

Attempted syntheses of perbromates were unsuccessful until 1968, when it was finally obtained by the

beta decay In nuclear physics, beta decay (β-decay) is a type of radioactive decay in which a beta particle (fast energetic electron or positron) is emitted from an atomic nucleus, transforming the original nuclide to an isobar of that nuclide. For ...

selenium-83 Selenium (34Se) has six natural isotopes that occur in significant quantities, along with the trace isotope 79Se, which occurs in minute quantities in uranium ores. Five of these isotopes are stable: 74Se, 76Se, 77Se, 78Se, and 80Se. The last th ...

in a

selenate The selenate ion is . Selenates are analogous to sulfates and have similar chemistry. They are highly soluble in aqueous solutions at ambient temperatures. Unlike sulfate, selenate is a somewhat good oxidizer; it can be reduced to selenite o ...

salt: : → + β⁻ Subsequently, it was successfully synthesized again by the

electrolysis In chemistry and manufacturing, electrolysis is a technique that uses direct electric current (DC) to drive an otherwise non-spontaneous chemical reaction. Electrolysis is commercially important as a stage in the separation of elements from n ...

of , although only in low yield. Later, it was obtained by the oxidation of

bromate The bromate anion, BrO, is a bromine-based oxoanion. A bromate is a chemical compound that contains this ion. Examples of bromates include sodium bromate, (), and potassium bromate, (). Bromates are formed many different ways in municipal drinki ...

with

xenon difluoride Xenon difluoride is a powerful fluorinating agent with the chemical formula , and one of the most stable xenon compounds. Like most covalent inorganic fluorides it is moisture-sensitive. It decomposes on contact with water vapor, but is otherwis ...

. Once perbromates are obtained,

can be produced by protonating . One effective method of producing perbromate is by the oxidation of

with

fluorine Fluorine is a chemical element with the symbol F and atomic number 9. It is the lightest halogen and exists at standard conditions as a highly toxic, pale yellow diatomic gas. As the most electronegative reactive element, it is extremely reacti ...

under alkaline conditions: : + + 2 → + 2 + This synthesis is much easier to perform on a large scale than the electrolysis route or oxidation by xenon difluoride. In 2011 a new, more effective synthesis was discovered: perbromate ions were formed through the reaction of

hypobromite The hypobromite ion, also called alkaline bromine water, is BrO−. Bromine is in the +1 oxidation state. The Br–O bond length is 1.82 Å. Hypobromite is the bromine compound analogous to hypochlorites found in common bleaches, and in immune ce ...

and bromate ions in an alkaline sodium hypobromite solution.

Diperiodatonickelate The periodatonickelates are a series of anions and salts of nickel complexed to the periodate anion. The diperiodatonickelates with nickel in the +4 oxidation state are powerful oxidising agents that are capable of oxidising bromate to perbromate. ...

anions in alkaline solution can oxidise bromate to perbromate. This is a relatively lower cost and fluorine free synthesis.

References

{{Reflist Perbromates

Synthesis

See also

References