The chlorite
ion
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 ...
, 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, p ...
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 symbol ...
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 i ...
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. C ...
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 quant ...
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 (C ...
.
Compounds
The free acid,
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 (C ...
HClO
2, 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 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 all ...
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 pa ...
(NaClO
2) being the only commercially important chlorite. Heavy metal chlorites (Ag
+, Hg
+, Tl
+, Pb
2+, and also Cu
2+ 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 ...
, NaClO
3. 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 ...
, ClO
2 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 pairs 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 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 ...
on the basis of standard
half cell
In electrochemistry, a half-cell is a structure that contains a conductive electrode and a surrounding conductive electrolyte separated by a naturally occurring Helmholtz double layer. Chemical reactions within this layer momentarily pump electri ...
potentials.
Uses
The most important chlorite is
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 pa ...
(NaClO
2); 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
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 ...
(ClO
2), normally via a reaction with HCl:
:5 NaClO
2 + 4 HCl → 5 NaCl + 4 ClO
2 + 2 H
2O
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
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 ...
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 oxide
Chlorine and oxygen can bond in many ways:
* chlorine monoxide, , chlorine (II) oxide
* chlorine peroxide, , dimer of chlorine (II) oxide
* chlorine dioxide, , chlorine (IV) oxide
* chloroperoxyl,
*chlorine trioxide, ClO3, chlorine (VI) oxide
* ...
s.
See also
*
Tetrachlorodecaoxide, a chlorite-based drug
*
Chloryl
In chemistry, chloryl refers to a triatomic cation with chemical formula . This species has the same general structure as chlorite () but it is electronically different, with chlorine having a +5 oxidation state (rather than the +3 of chlorit ...
,
References
{{Reflist
*''Kirk-Othmer Concise Encyclopedia of Chemistry'', Martin Grayson, Editor, John Wiley & Sons, Inc., 1985
Chlorine oxides