The chlorite ion, or chlorine dioxide

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 conve ...

, is the

halite Halite (), commonly known as rock salt, is a type of salt, the mineral (natural) form of sodium chloride ( Na Cl). Halite forms isometric crystals. The mineral is typically colorless or white, but may also be light blue, dark blue, purple, ...

with the

chemical formula In chemistry, a chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, ...

of . A chlorite (compound) is a compound that contains this group, with

chlorine Chlorine is a chemical element with the 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 between them. Chlorine is ...

in 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. ...

of +3. Chlorites are also known as

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 quanti ...

s of

chlorous acid Chlorous acid is an inorganic compound with the formula HClO2. It is a weak acid. Chlorine has oxidation state +3 in this acid. The pure substance is unstable, disproportionating to hypochlorous acid (Cl oxidation state +1) and chloric acid (Cl ...

Compounds

The free acid,

HClO₂, is the least stable

oxoacid An oxyacid, oxoacid, or ternary acid is an acid that contains oxygen. Specifically, it is a compound that contains hydrogen, oxygen, and at least one other element, with at least one hydrogen atom bonded to oxygen that can dissociate to produce ...

of chlorine and has only been observed as an

aqueous solution An aqueous solution is a solution in which the solvent is water. It is mostly shown in chemical equations by appending (aq) to the relevant chemical formula. For example, a solution of table salt, or sodium chloride (NaCl), in water would ...

at low concentrations. Since it cannot be concentrated, it is not a commercial product. The alkali metal and

alkaline earth metal The alkaline earth metals are six chemical elements in group 2 of the periodic table. They are beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).. The elements have very similar properties: they are ...

compounds are all colorless or pale yellow, with

sodium chlorite Sodium chlorite (NaClO2) is a chemical compound used in the manufacturing of paper and as a disinfectant. Use The main application of sodium chlorite is the generation of chlorine dioxide for bleaching and stripping of textiles, pulp, and pap ...

(NaClO₂) being the only commercially important chlorite. Heavy metal chlorites (Ag⁺, Hg⁺, Tl⁺, Pb²⁺, and also Cu²⁺ and ) are unstable and decompose explosively with heat or shock. Sodium chlorite is derived indirectly from

sodium chlorate Sodium chlorate is an inorganic compound with the chemical formula Na ClO3. It is a white crystalline powder that is readily soluble in water. It is hygroscopic. It decomposes above 300 °C to release oxygen and leaves sodium chloride. Sever ...

, NaClO₃. First, the explosively unstable gas

chlorine dioxide Chlorine dioxide is a chemical compound with the formula ClO2 that exists as yellowish-green gas above 11 °C, a reddish-brown liquid between 11 °C and −59 °C, and as bright orange crystals below −59 °C. It is usually ...

, ClO₂ is produced by reducing sodium chlorate with a suitable reducing agent such as methanol, hydrogen peroxide, hydrochloric acid or sulfur dioxide.

Structure and properties

The chlorite ion adopts a bent molecular geometry, due to the effects of the

lone pair In chemistry, a lone pair refers to a pair of valence electrons that are not shared with another atom in a covalent bondIUPAC '' Gold Book'' definition''lone (electron) pair''/ref> and is sometimes called an unshared pair or non-bonding pair. L ...

s on the chlorine atom, with an O–Cl–O bond angle of 111° and Cl–O bond lengths of 156 pm. Chlorite is the strongest oxidiser of the chlorine oxyanions on the basis of standard half cell potentials.

Uses

The most important chlorite is

(NaClO₂); this is used in the bleaching of textiles, pulp, and paper, however despite its strongly oxidizing nature it is often not used directly being instead used to generate the neutral species

(ClO₂), normally via a reaction with HCl: :5 NaClO₂ + 4 HCl → 5 NaCl + 4 ClO₂ + 2 H₂O

Other oxyanions

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 chlorine exist, in which it can assume

s of −1, +1, +3, +5, or +7 within the corresponding anions Cl⁻, ClO⁻, , , or , known commonly and respectively as chloride, hypochlorite, chlorite, chlorate, and perchlorate. These are part of a greater family of other chlorine oxides.

References

{{Reflist *''Kirk-Othmer Concise Encyclopedia of Chemistry'', Martin Grayson, Editor, John Wiley & Sons, Inc., 1985 Chlorine oxides

Compounds

Structure and properties

Uses

Other oxyanions

See also

References