Potassium iodide

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Potassium iodide

Potassium iodide is an inorganic compoundInorganic compound

An inorganic compound is a chemical compound that is not an organic compound....
with formulaChemical formula

A chemical formula is a concise way of expressing information about the atoms that constitute a particular chemical compoun...
KPotassium

Potassium is a chemical element. It has the symbol K and atomic number 19....
IIodide

An iodide ion is an iodine atom with a −1 charge....
. This colorless salt is the most commercially significant iodide compound, approximately 37,000 tons/y were produced in 1985. It is less hygroscopic than sodium iodideSodium iodide

Sodium iodide is a white, crystalline salt with chemical formula NaI used in radiation dectection, treatment of iodine defic...
, making it easier to work with. Aged and impure samples are yellow because of oxidation of the iodideIodide

An iodide ion is an iodine atom with a −1 charge....
to iodineIodine

Iodine , is a chemical element in the periodic table that has the symbol I and atomic number 53....
.

Structure, production, properties

Potassium iodide is ionIon

An ion is an atom or group of atoms that normally are electrically neutral and achieve their status as an ion by loss of an...
ic, K⁺I^-. It crystallises in the sodium chlorideSodium chloride

Sodium chloride, also known as common salt, table salt, or halite, is a chemical compound with the formula NaCl....
motif. It is produced industrial by treating KOH with iodine.

Inorganic chemistry

Since the iodideIodide

An iodide ion is an iodine atom with a −1 charge....
ion is a mild reducing agentRedox

Redox reactions include all chemical processes in which atoms have their oxidation number changed....
, I^- is easily oxidised to I₂Iodine

Iodine , is a chemical element in the periodic table that has the symbol I and atomic number 53....
by powerful oxidising agentsRedox

Redox reactions include all chemical processes in which atoms have their oxidation number changed....
such as chlorineChlorine

Chlorine , is the chemical element with atomic number 17 and symbol Cl....
:

2 KI(aqAqueous Overview

Aqueous means pertaining to, related to, similar to, or dissolved in water....
) + Cl₂(aq) ? 2 KClPotassium chloride Summary

The chemical compound potassium chloride is a metal halide composed of potassium and chlorine....
+ I₂(aq)

This reaction is employed in the isolation of iodine from natural sources. Even air will oxidize iodide as evidenced by the observation of a purple extract when aged samples of KI are rinsed with dichloromethaneDichloromethane

Dichloromethane or methylene chloride is the chemical compound with the formula CH2Cl2....
. As formed under acidic conditions, hydroiodic acid (HI) is a stronger reducing agent.

Like other iodide salts, KI forms I₃^-Triiodide

Triiodide is an anion composed of three iodine atoms....
when combined with elemental iodineIodine

Iodine , is a chemical element in the periodic table that has the symbol I and atomic number 53....
.

KI(aq) + I₂Iodine

Iodine , is a chemical element in the periodic table that has the symbol I and atomic number 53....
(sSolid

A solid object is in the phase of matter characterized by resistance to deformation and changes of volume....
) ? KI₃(aq)

Unlike I₂, I₃^- salts can be highly water-soluble. Through this reaction iodineIodine

Iodine , is a chemical element in the periodic table that has the symbol I and atomic number 53....
is used in redoxFacts About Redox

Redox reactions include all chemical processes in which atoms have their oxidation number changed....
titrationTitration

Titration is a standard laboratory method of quantitative/chemical analysis which can be used to determine the concentration...
s. Aqueous KI₃, "Lugol's solution," are used as disinfectants and as etchants for gold surfaces.

Potassium iodide is the precursor to silver(I) iodide, which are used for high speed photographic filmPhotographic film

Photographic film is a sheet of plastic coated with an emulsion containing light-sensitive silver halide salts with variab...
:

Organic chemistry

KI serves as a source of iodide in organic synthesisOrganic synthesis

Organic synthesis is the construction of organic molecules via chemical processes....
. A useful application is in the preparation of aryl iodides from arenediazonium salts. For example:

Applications

The major uses of KI include nutritional supplement in animal feeds, a precursor to AgI, and as a component in disinfectants. Potassium iodide is also added to table saltSodium chloride

Sodium chloride, also known as common salt, table salt, or halite, is a chemical compound with the formula NaCl....
in small quantities to make it "iodized." KI is also used as a fluorescence quenching agent in biomedical research because of collisional quenching by its iodide ion. A saturated solution of potassium iodide, abbreviated SSKI, is also used as treatment for sporotrichosisSporotrichosis

Sporotrichosis is a disease caused by the infection of the fungus Sporothrix schenckii....
, a fungal infection.

Radiation protection

Following the Chernobyl nuclear reactor disasterChernobyl disaster

The Chernobyl disaster occurred at 01:23 a.m....
in April, 1986, a saturated solution of potassium iodide was administered to 10.5 million children and 7 million adults in PolandPoland

Poland , officially the Republic of Poland , is a country located in Central Europe....
as a prophylactic measure against accumulation of radioactive iodine-131Iodine-131

Iodine-131, also called radioiodine, is a radioisotope of iodine....
in the thyroidThyroid

The thyroid is one of the larger endocrine glands in the body....
gland.

Potassium iodide was also approved in 1982 by the US FDA to protect the thyroidThyroid

The thyroid is one of the larger endocrine glands in the body....
glands from radioactive iodine. In the event of an accident or attack at a nuclear power plantNuclear power plant

A nuclear power plant is a thermal power station in which the heat source is one or more nuclear reactors....
, or fallout from a nuclear bomb, several volatile fission product radionuclides may be released. ¹³¹IFacts About Iodine-131

Iodine-131, also called radioiodine, is a radioisotope of iodine....
is a common fission by-product and is particularly dangerous as the body concentrates it in the thyroid gland, which may lead to thyroid cancer. By saturating the body with a source of stable iodide prior to exposure, inhaled or ingested ¹³¹I tends to be excreted. Potassium iodide cannot protect against any other causes of radiation poisoningFacts About Radiation poisoning

Radiation poisoning, also called "radiation sickness", is a form of damage to organic tissue due to excessive exposure to io...
, however, nor can it provide any degree of protection against most forms of "dirty bombDirty bomb

The term dirty bomb is most often used to refer to a Radiological Dispersal Device , a radiological weapon which comb...
s." In case of a nuclear emergencyNuclear fallout

Fallout is the residual radiation hazard from a nuclear explosion, so named because it "falls out" of the atmosphere into wh...
, iodineIodine

Iodine , is a chemical element in the periodic table that has the symbol I and atomic number 53....
used for the cleaning of wounds should not be ingested, as it is poisonous.

Recommended Dosage for Radiological Emergencies involving radioactive iodine
Age	>-	Over 12 years old	130
3 - 12 years old	65
1 - 36 months old	32
< 1 month old	16

See fission products and the external links for more details.

Precautions

Mild irritant, wear gloves. Chronic overexposure can have adverse effects on the thyroid.

External links

Potassium Iodide Information