Record Information
Creation date2010-04-08 22:05:53 UTC
Update date2019-11-26 02:59:26 UTC
Primary IDFDB003635
Secondary Accession Numbers
  • FDB030914
Chemical Information
FooDB NameIodine
DescriptionElemental iodine (I2) is poisonous if taken orally in larger amounts; 2?3 grams of it is a lethal dose for an adult human.; Elemental iodine is an oxidizing irritant and direct contact with skin can cause lesions, so iodine crystals should be handled with care. Solutions with high elemental iodine concentration such as tincture of iodine are capable of causing tissue damage if use for cleaning and antisepsis is prolonged.; In many ways, 129I is similar to 36Cl. It is a soluble halogen, fairly non-reactive, exists mainly as a non-sorbing anion, and is produced by cosmogenic, thermonuclear, and in-situ reactions. In hydrologic studies, 129I concentrations are usually reported as the ratio of 129I to total I (which is virtually all 127I). As is the case with 36Cl/Cl, 129I/I ratios in nature are quite small, 10?14 to 10?10 (peak thermonuclear 129I/I during the 1960s and 1970s reached about 10?7). 129I differs from 36Cl in that its halflife is longer (15.7 vs. 0.301 million years), it is highly biophilic, and occurs in multiple ionic forms (commonly, I? and IO3?) which have different chemical behaviors. This makes it fairly easy for 129I to enter the biosphere as it becomes incorporated into vegetation, soil, milk, animal tissue, etc.; Iodic acid (HIO3) and its salts are strong oxidizers. Periodic acid (HIO4) cleaves vicinal diols along the C-C bond to give aldehyde fragments. 2-Iodoxybenzoic acid and Dess-Martin periodinane are hypervalent iodine oxidants used to specifically oxidize alcohols to ketones or aldehydes. Iodine pentoxide is a strong oxidant as well.; Iodine (pronounced /?a?.?da?n/ EYE-o-dyne, /?a?.?d?n/ EYE-o-d?n, or in chemistry /?a?.?di?n/ EYE-o-deen; from Greek: ????? iodes "violet"), is a chemical element that has the symbol I and atomic number 53. Naturally-occurring iodine is a single isotope with 74 neutrons. Chemically, iodine is the second least reactive of the halogens, and the second most electropositive halogen, trailing behind astatine in both of these categories. However, the element does not occur in the free state in nature. As with all other halogens (members of Group 17 in the periodic table), when freed from its compounds iodine forms diatomic molecules (I2).; Iodine forms many compounds. Potassium iodide is the most commercially significant iodine compound. It is a convenient source of the iodide anion; it is easier to handle than sodium iodide because it is not hygroscopic. Sodium iodide is especially useful in the Finkelstein reaction, because it is soluble in acetone, while potassium iodide is poorly so. In this reaction, an alkyl chloride is converted to an alkyl iodide. This relies on the insolubility of sodium chloride in acetone to drive the reaction:; Iodine is a common general stain used in thin-layer chromatography. It is also used in the Gram stain as a mordant, after the sample is treated with crystal violet.; Iodine is an essential trace element for life, the heaviest element commonly needed by living organisms, and the second-heaviest known to be used by any form of life (only tungsten, a component of a few bacterial enzymes, has a higher atomic number and atomic weight). Iodine's main role in animal biology is as constituents of the thyroid hormones, thyroxine (T4) and triiodothyronine (T3). These are made from addition condensation products of the amino acid tyrosine, and are stored prior to release in an iodine-containing protein called thyroglobulin. T4 and T3 contain four and three atoms of iodine per molecule, respectively. The thyroid gland actively absorbs iodide from the blood to make and release these hormones into the blood, actions which are regulated by a second hormone TSH from the pituitary. Thyroid hormones are phylogenetically very old molecules which are synthesized by most multicellular organisms, and which even have some effect on unicellular organisms.; Iodine is an essential trace element. Chemically, iodine is the least reactive of the halogens, and the most electropositive halogen after astatine. However, iodine does not occur in the free state in nature. As with all other halogens , when freed from its compounds iodine forms diatomic molecules (I2).; Iodine and its compounds are primarily used in medicine, photography, and dyes. Iodine is required for the production of thyroid hormones, which are essential for normal brain development, and the fetus, newborn, and young child are particularly vulnerable to iodine deficiency. Physiologically, iodine exists as an ion in the body. The iodine requirement increases during pregnancy and recommended intakes are in the range of 220-250 microg/day. Monitoring iodine status during pregnancy is a challenge. New recommendations from World Health Organization suggest that a median urinary iodine concentration >250 microg/L and <500 microg/L indicates adequate iodine intake in pregnancy. Based on this range, it appears that many pregnant women in have inadequate intakes. Thyroid-stimulating hormone concentration in the newborn is a sensitive indicator of mild iodine deficiency in late pregnancy. The potential adverse effects of mild iodine deficiency during pregnancy are uncertain. Controlled trials of iodine supplementation in mildly iodine-deficient pregnant women suggest beneficial effects on maternal and newborn serum thyroglobulin and thyroid volume, but no effects on maternal and newborn total or free thyroid hormone concentrations. There are no long-term data on the effect of iodine supplementation on birth outcomes or infant development. New data from well-controlled studies indicate that iodine repletion in moderately iodine-deficient school-age children has clear benefits: it improves cognitive and motor function; Iodine under standard conditions is a shiny grey solid. It can be seen apparently sublimating at standard temperatures into a violet-pink gas that has an irritating odor. This halogen forms compounds with many elements, but is less reactive than the other members of its Group VII (halogens) and has some metallic light reflectance.; Iodine-129 (129I; half-life 15.7 million years) is a product of cosmic ray spallation on various isotopes of xenon in the atmosphere, in cosmic ray muon interaction with tellurium-130, and also uranium and plutonium fission, both in subsurface rocks and nuclear reactors. Artificial nuclear processes, in particular nuclear fuel reprocessing and atmospheric nuclear weapons tests, have now swamped the natural signal for this isotope. Nevertheless, it now serves as a groundwater tracer as indicator of nuclear waste dispersion into the natural environment. In a similar fashion, 129I was used in rainwater studies to track fission products following the Chernobyl disaster.; The most common compounds of iodine are the iodides of sodium (NaI) and potassium (KI) and the iodates (KIO3), as elemental iodine is mildly toxic to all living things. Normal iodine is an essential precursor for the manufacture of thyroid hormone.; it also increases concentrations of insulin-like growth factor 1 and insulin-like growth factor-binding protein 3, and improves somatic growth. (PMID: 17956157). Iodine is found in many foods, some of which are tartary buckwheat, abalone, black chokeberry, and winter savory.
CAS Number7553-56-2
Molecular iodineChEBI
Tincture iodineHMDB
Iodine 127MeSH, HMDB
Iodine-127MeSH, HMDB
Cadex (TN)biospider
Diatomic iodinebiospider
HSDB 34biospider
IEF-Marker fluorescent pI 2.1biospider
Iode Oligosol Liq 0.024mg/2mlbiospider
Iodine ((127)I2)biospider
Iodine (JP15/USP)biospider
Iodine (resublimed)biospider
Iodine [jan]biospider
Iodine according to hanus for the iodine value determinationbiospider
Iodine colloidalbiospider
Iodine crystalsbiospider
Iodine Liquid (S#125)biospider
Iodine sublimedbiospider
Iodine Tct 2%biospider
Iodine tincturebiospider
Iodine tincture uspbiospider
Iodine, acsbiospider
Iodum Dps D3-C1000biospider
Iodum Gtte 4ch-30chbiospider
Iosan superdipbiospider
Kelpasan-Tab 0.05mgbiospider
Lipiodol Ultra Fluide 38%biospider
Liquid iodinebiospider
Lugols Soln 5%biospider
Nature's fingerprint kelp capsulesbiospider
Opti-iodine capletsbiospider
Pariodex Liq 10%biospider
Plexa dulsin liqbiospider
Povidone iodine ontbiospider
Povidone iodine prep padbiospider
Povidone Iodine Scrub Swabstick 0.75%biospider
Solunet 1 Brosse 0.75%biospider
Solunet 1 Eponge 0.75%biospider
Spray I Dene 0.5%biospider
Predicted Properties
Physiological Charge0ChemAxon
Hydrogen Acceptor Count0ChemAxon
Hydrogen Donor Count0ChemAxon
Polar Surface Area0 ŲChemAxon
Rotatable Bond Count0ChemAxon
Refractivity26.68 m³·mol⁻¹ChemAxon
Polarizability10.18 ųChemAxon
Number of Rings0ChemAxon
Rule of FiveYesChemAxon
Ghose FilterNoChemAxon
Veber's RuleYesChemAxon
MDDR-like RuleNoChemAxon
Chemical FormulaI2
IUPAC namediiodine
InChI IdentifierInChI=1S/I2/c1-2
Average Molecular Weight253.8089
Monoisotopic Molecular Weight253.80893684
Description Belongs to the class of inorganic compounds known as homogeneous halogens. These are inorganic non-metallic compounds in which the largest atom is a nobel gas.
KingdomInorganic compounds
Super ClassHomogeneous non-metal compounds
ClassHomogeneous halogens
Sub ClassNot Available
Direct ParentHomogeneous halogens
Alternative ParentsNot Available
  • Homogeneous halogen
Molecular FrameworkNot Available
External Descriptors
Physiological effect

Health effect:


Route of exposure:


Biological location:


Industrial application:

Biological role:

Physico-Chemical Properties - Experimental
Physico-Chemical Properties - Experimental
Physical stateSolid
Physical DescriptionNot Available
Mass CompositionNot Available
Melting Point113.6 oC
Boiling PointNot Available
Experimental Water Solubility0.33 mg/mL at 25 oCCLAYTON,GD & CLAYTON,FE (1994)
Experimental logP2.49HANSCH,C ET AL. (1995)
Experimental pKaNot Available
Isoelectric pointNot Available
Optical RotationNot Available
Spectroscopic UV DataNot Available
DensityNot Available
Refractive IndexNot Available
TypeDescriptionSplash KeyView
Predicted GC-MSIodine, non-derivatized, Predicted GC-MS Spectrum - 70eV, Positivesplash10-0udi-0090000000-0b4eb980a6d80c2892ddSpectrum
Predicted GC-MSIodine, non-derivatized, Predicted GC-MS Spectrum - 70eV, PositiveNot AvailableSpectrum
TypeDescriptionSplash KeyView
Predicted MS/MSPredicted LC-MS/MS Spectrum - 10V, Positivesplash10-0udi-0090000000-776e7d808857b52aa5942015-09-15View Spectrum
Predicted MS/MSPredicted LC-MS/MS Spectrum - 20V, Positivesplash10-0udi-0090000000-776e7d808857b52aa5942015-09-15View Spectrum
Predicted MS/MSPredicted LC-MS/MS Spectrum - 40V, Positivesplash10-0udi-0090000000-776e7d808857b52aa5942015-09-15View Spectrum
Predicted MS/MSPredicted LC-MS/MS Spectrum - 10V, Negativesplash10-0udi-0090000000-9f41876d0a547fca82582015-09-15View Spectrum
Predicted MS/MSPredicted LC-MS/MS Spectrum - 20V, Negativesplash10-0udi-0090000000-9f41876d0a547fca82582015-09-15View Spectrum
Predicted MS/MSPredicted LC-MS/MS Spectrum - 40V, Negativesplash10-0udi-0090000000-9f41876d0a547fca82582015-09-15View Spectrum
Predicted MS/MSPredicted LC-MS/MS Spectrum - 10V, Positivesplash10-0udi-0090000000-d80218a1199b8de0e8432021-09-22View Spectrum
Predicted MS/MSPredicted LC-MS/MS Spectrum - 20V, Positivesplash10-0udi-0090000000-d80218a1199b8de0e8432021-09-22View Spectrum
Predicted MS/MSPredicted LC-MS/MS Spectrum - 40V, Positivesplash10-0udi-0090000000-d80218a1199b8de0e8432021-09-22View Spectrum
NMRNot Available
ChemSpider ID785
KEGG Compound IDC01382
Pubchem Compound ID807
Pubchem Substance IDNot Available
ChEBI ID17606
Phenol-Explorer IDNot Available
DrugBank IDDB05247
CRC / DFC (Dictionary of Food Compounds) IDNot Available
EAFUS IDNot Available
BIGG ID37476
KNApSAcK IDNot Available
HET IDNot Available
Food Biomarker OntologyNot Available
VMH IDNot Available
Flavornet IDNot Available
GoodScent IDNot Available
SuperScent IDNot Available
Wikipedia IDIodine
Phenol-Explorer Metabolite IDNot Available
Duplicate IDSNot Available
Old DFC IDSNot Available
Associated Foods
FoodContent Range AverageReference
Biological Effects and Interactions
Health Effects / Bioactivities
acnegenic52209 A role played by the molecular entity or part thereof which causes the development of a pathological process.DUKE
anti bacterial33282 A substance that kills or slows the growth of bacteria.DUKE
anti goiter52217 Any substance introduced into a living organism with therapeutic or diagnostic purpose.DUKE
anti septic33281 A substance that kills or slows the growth of microorganisms, including bacteria, viruses, fungi and protozoans.DUKE
anti thyrotoxic50247 Any protective agent counteracting or neutralizing the action of poisons.DUKE
anti viral22587 A substance that destroys or inhibits replication of viruses.DUKE
fungicide24127 A substance used to destroy fungal pests.DUKE
EnzymesNot Available
PathwaysNot Available
MetabolismNot Available
BiosynthesisNot Available
Organoleptic Properties
FlavoursNot Available
Synthesis ReferenceNot Available
General ReferenceNot Available
Content Reference— Saxholt, E., et al. 'Danish food composition databank, revision 7.' Department of Nutrition, National Food Institute, Technical University of Denmark (2008).
— Duke, James. 'Dr. Duke's Phytochemical and Ethnobotanical Databases. United States Department of Agriculture.' Agricultural Research Service, Accessed April 27 (2004).
— U.S. Department of Agriculture, Agricultural Research Service. 2008. USDA National Nutrient Database for Standard Reference, Release 21. Nutrient Data Laboratory Home Page.