53 tellurium ← iodine → xenon Br ↑ I ↓ At Periodic Table - Extended Periodic Table
General
Name, Symbol, Number	iodine, I, 53
Chemical series	halogens
Group, Period, Block	17, 5, p
Appearance	violet-dark gray, lustrous
Standard atomic weight	126.90447(3)  g·mol−1
Electron configuration	[Kr] 4d10 5s2 5p5
Electrons per shell	2, 8, 18, 18, 7
Physical properties
Phase	solid
Density (near r.t.)	4. Tellurium (tɪˈlʊəriəm/ /tɛl- is a Chemical element that has the symbol Te and Atomic number 52 Xenon (ˈzɛnɒn or) is a Chemical element represented by the symbol Xe. Astatine (ˈæstətiːn is a Radioactive Chemical element with the symbol At and Atomic number 85 This is a typical display of the periodic table of the elements and contains the symbol and Atomic number of each element Wikipedia talkFeatured lists for an explanation of this and other inclusion tags below -->This is a list of Chemical elements, sorted by name Wikipedia talkFeatured lists for an explanation of this and other inclusion tags below -->This is a list of chemical elements by symbol, including the A table of Chemical elements ordered by Atomic number and color coded according to type of element In Chemistry a group, also known as a family, is a vertical column in the Periodic table of the Chemical elements There are 18 groups in Abundance Owing to their high Reactivity, the halogens are found in the environment only in compounds or as Ions Halide ions and oxoanions In Chemistry a group, also known as a family, is a vertical column in the Periodic table of the Chemical elements There are 18 groups in In the Periodic table of the elements, a period is a horizontal row of the table A block of the Periodic table of elements is a set of adjacent groups The respective highest-energy electrons in each element in a block belong to the same Atomic Abundance Owing to their high Reactivity, the halogens are found in the environment only in compounds or as Ions Halide ions and oxoanions A period 5 element is one of the Chemical elements in the fifth row (or period) of the periodic table of the elements. See also Electron configuration The atomic mass (ma is the Mass of an atom most often expressed in unified atomic mass units The atomic mass may be considered to be the total mass To help compare different orders of magnitude, the following list describes various Mass levels between 10&minus36&thinsp kg and 1053&thinspkg In Atomic physics and Quantum chemistry, electron configuration is the arrangement of Electrons in an Atom, Molecule, or other Krypton (ˈkrɪptən or /ˈkrɪptɒn/ from kryptos "hidden" is a Chemical element with the symbol Kr and Atomic number 36 The electron is a fundamental Subatomic particle that was identified and assigned the negative charge in 1897 by J An electron shell may be crudely thought of as an Orbit followed by Electrons around an Atom nucleus. In the Physical sciences a phase is a Set of states of a macroscopic physical system that have relatively uniform chemical composition and physical properties A solid' object is in the States of matter characterized by resistance to Deformation and changes of Volume. The density of a material is defined as its Mass per unit Volume: \rho = \frac{m}{V} Different materials usually have different Room temperature (also referred to as ambient temperature) is a common term to denote a certain Temperature within enclosed space at which humans are accustomed 933  g·cm−3
Melting point	386. The melting point of a solid is the temperature range at which it changes state from solid to Liquid. 85 K (113. The kelvin (symbol K) is a unit increment of Temperature and is one of the seven SI base units The Kelvin scale is a thermodynamic 7 °C, 236. The Celsius Temperature scale was previously known as the centigrade scale. 66 °F)
Boiling point	457. Fahrenheit is a temperature scale named after Daniel Gabriel Fahrenheit (1686–1736 a German Physicist who proposed it in 1724 The boiling point of a liquid is the temperature at which the Vapor pressure of the liquid equals the environmental pressure surrounding the liquid 4 K (184. The kelvin (symbol K) is a unit increment of Temperature and is one of the seven SI base units The Kelvin scale is a thermodynamic 3 °C, 363. The Celsius Temperature scale was previously known as the centigrade scale. 7 °F)
Critical point	819 K, 11. Fahrenheit is a temperature scale named after Daniel Gabriel Fahrenheit (1686–1736 a German Physicist who proposed it in 1724 In Physical chemistry, Thermodynamics, Chemistry and Condensed matter physics, a critical point, also called a critical state The kelvin (symbol K) is a unit increment of Temperature and is one of the seven SI base units The Kelvin scale is a thermodynamic 7 MPa
Heat of fusion	(I2) 15. The standard Enthalpy of fusion (symbol \Delta{}H_{fus} also known as the heat of fusion or specific melting heat, is the amount of 52  kJ·mol−1
Heat of vaporization	(I2) 41. The joule per mole (symbol J·mol-1 is an SI derived unit of energy per amount of material The enthalpy of vaporization, (symbol \Delta{}_{v}H also known as the heat of vaporization or heat of evaporation, is the Energy required 57  kJ·mol−1
Specific heat capacity	(25 °C) (I2) 54. The joule per mole (symbol J·mol-1 is an SI derived unit of energy per amount of material Specific heat capacity, also known simply as specific heat, is the measure of the heat energy required to increase the Temperature of a unit quantity 44  J·mol−1·K−1
Vapor pressure (rhombic) P(Pa) 1 10 100 1 k 10 k 100 k at T(K) 260 282 309 342 381 457
Atomic properties
Crystal structure	orthorhombic
Oxidation states	±1, 5, 7 (strongly acidic oxide)
Electronegativity	2. Vapor pressure (also known as equilibrium vapor pressure or saturation vapor pressure) is the Pressure of a Vapor in equilibrium In Mineralogy and Crystallography, a crystal structure is a unique arrangement of Atoms in a Crystal. In Chemistry, the oxidation state is an indicator of the degree of Oxidation of an Atom in a Chemical compound. In Computer science, ACID ( Atomicity Consistency Isolation Durability) is a set of properties that guarantee that Database transactions are " Electronegativity " is the opposite of " Electropositivity," which describes an element's ability to donate electrons 66 (Pauling scale)
Ionization energies	1st: 1008. The ionization potential, ionization energy or EI of an Atom or Molecule is the Energy required to remove an Electron 4 kJ/mol
	2nd: 1845. The joule per mole (symbol J·mol-1 is an SI derived unit of energy per amount of material 9 kJ/mol
	3rd: 3180 kJ/mol
Atomic radius	140  pm
Atomic radius (calc. Atomic radius, and more generally the size of an atom, is not a precisely defined Physical quantity, nor is it constant in all circumstances A picometre ( American spelling: picometer, symbol pm) is a unit of Length in the Metric system, equal to one trillionth )	115  pm
Covalent radius	133  pm
Van der Waals radius	198 pm
Miscellaneous
Magnetic ordering	nonmagnetic
Electrical resistivity	(0 °C) 1. The covalent radius, r cov is a measure of the size of Atom which forms part of a Covalent bond. Van der Waals Volume The van der Waals volume, V, also called the atomic volume or molecular volume, is the atomic property most directly In Physics, magnetism is one of the Phenomena by which Materials exert attractive or repulsive Forces on other Materials. Electrical resistivity (also known as specific electrical resistance) is a measure of how strongly a material opposes the flow of Electric current. 3×107 Ω·m
Thermal conductivity	(300 K) 0. In Physics, thermal conductivity, k is the property of a material that indicates its ability to conduct Heat. 449  W·m−1·K−1
Bulk modulus	7. 7  GPa
CAS registry number	7553-56-2
Selected isotopes
Main article: Isotopes of iodine iso NA half-life DM DE (MeV) DP 127I 100% 127I is stable with 74 neutrons 129I syn 15. CAS registry numbers are unique numerical identifiers for Chemical compounds Polymers biological sequences mixtures and Alloys They are also referred to There are 37 Isotopes of Iodine ( I) and only one 127I is stable Isotopes (Greek isos = "equal" tópos = "site place" are any of the different types of atoms ( Nuclides In Chemistry, natural abundance (NA refers to the abundance Isotopes of a Chemical element as naturally found on a planet Half-Life (computer-game page here It's already listed in the disambiguation page Radioactive decay is the process in which an unstable Atomic nucleus loses energy by emitting ionizing particles and Radiation. The decay energy is the Energy released by a Nuclear decay. The energy difference of the Reactants is often written as Q: where Q In Nuclear physics, a decay product, also known as a daughter product, daughter isotope or daughter nuclide, is a Nuclide Stable isotopes are chemical isotopes that are not Radioactive (to current knowledge This article is a discussion of neutrons in general For the specific case of a neutron found outside the nucleus see Free neutron. A synthetic radioisotope is a Radionuclide that is not found in nature no natural process or mechanism exists which produces it or it is so unstable that it decays away in 7×106y β- 0. A year (from Old English gēr) is the time between two recurrences of an event related to the Orbit of the Earth around the Sun In Nuclear physics, beta decay is a type of Radioactive decay in which a Beta particle (an Electron or a Positron) is emitted 194 129Xe 131I syn 8. Xenon (ˈzɛnɒn or) is a Chemical element represented by the symbol Xe. A synthetic radioisotope is a Radionuclide that is not found in nature no natural process or mechanism exists which produces it or it is so unstable that it decays away in 02070 d β- 0. A day (symbol d is a unit of Time equivalent to 24 Hours and the duration of a single Rotation of planet Earth with respect to the In Nuclear physics, beta decay is a type of Radioactive decay in which a Beta particle (an Electron or a Positron) is emitted 971 131Xe
References

Iodine
Identifiers
CAS number	[7553-56-2]
Hazards
R-phrases	R21 R23 R25 R34
S-phrases	S23 S25
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Iodine (IPA: /ˈaɪədaɪn, ˈaɪədɪn/, or /ˈaɪədiːn/; from Greek: ιώδης iodes "violet"), is a chemical element that has the symbol I and atomic number 53. Xenon (ˈzɛnɒn or) is a Chemical element represented by the symbol Xe. Recommended values for many properties of the elements together with various references are collected on these data pages CAS registry numbers are unique numerical identifiers for Chemical compounds Polymers biological sequences mixtures and Alloys They are also referred to R-phrases (short for Risk Phrases) are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous R-phrases (short for Risk Phrases) are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous R-phrases (short for Risk Phrases) are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous R-phrases (short for Risk Phrases) are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous R-phrases (short for Risk Phrases) are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. In Chemistry, the standard state of a material is its state at 1 bar (100 Kilopascals exactly Greek (el ελληνική γλώσσα or simply el ελληνικά — "Hellenic" is an Indo-European language, spoken today by 15-22 million people mainly A chemical element is a type of Atom that is distinguished by its Atomic number; that is by the number of Protons in its nucleus. See also List of elements by atomic number In Chemistry and Physics, the atomic number (also known as the proton Naturally-occurring iodine is a single isotope with 74 neutrons.

Chemically, iodine is the least reactive of the halogens, and the most electropositive halogen after astatine. Abundance Owing to their high Reactivity, the halogens are found in the environment only in compounds or as Ions Halide ions and oxoanions " Electronegativity " is the opposite of " Electropositivity," which describes an element's ability to donate electrons Astatine (ˈæstətiːn is a Radioactive Chemical element with the symbol At and Atomic number 85 However, the element does not occur in the free state in nature. As with all other halogens (members of Group VII in the Periodic Table), when freed from its compounds iodine forms diatomic molecules (I₂). Abundance Owing to their high Reactivity, the halogens are found in the environment only in compounds or as Ions Halide ions and oxoanions Diatomic molecules are molecules made only of two Atoms of either the same or different Chemical elements The prefix di- means two in Greek In Chemistry, a molecule is defined as a sufficiently stable electrically neutral group of at least two Atoms in a definite arrangement held together by

Iodine and its compounds are primarily used in medicine, photography and in dyes. Medicine is the art and science of healing It encompasses a range of Health care practices evolved to maintain and restore Human Health by the Photography (fә'tɒgrәfi or fә'tɑːgrәfi (from Greek φωτο and γραφία is the process and Art of recording pictures by means of capturing A dye can generally be described as a Colored substance that has an affinity to the substrate to which it is being applied Although it is rare in the solar system and Earth's crust, the iodides are very soluble in water, and the element is concentrated in seawater. The Solar System consists of the Sun and those celestial objects bound to it by Gravity. In Geology, a crust is the outermost solid shell of a planet or moon This mechanism helps to explain how the element came to be required in trace amounts by all animals and some plants, being by far the heaviest element known to be necessary to living organisms.

Contents 1 Properties 2 History 3 Applications 4 Occurrence on earth 5 Sources 6 Descriptive chemistry 7 Notable inorganic iodine compounds 8 Stable iodine in biology 8.1 Human dietary intake 8.2 Iodine deficiency 9 Radioiodine and biology 9.1 Radioiodine and the thyroid 9.2 Radioiodine and the kidney 10 Isotopes 11 Toxicity of iodine 12 Precautions for stable iodine 13 Clandestine use 14 See also 15 References 16 External links

Properties

Iodine under standard conditions is a dark-purple/dark-brown solid. It can be seen apparently subliming at standard temperatures into a violet-pink gas that has an irritating odor. Sublimation of an element or compound is a transition from the Solid to Gas phase with no intermediate liquid stage 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.

Elemental iodine dissolves easily in chloroform and carbon tetrachloride. Chloroform, also known as trichloromethane and methyl trichloride, is a Chemical compound with formula C[[Hydrogen H]] Cl Carbon tetrachloride, also known by many other names (see Table is the Organic compound with the formula CCl4 The solubility of elementary iodine in water can be vastly increased by the addition of potassium iodide. The molecular iodine reacts reversibly with the negative ion, creating the triiodide anion, I₃⁻, which dissolves well in water. In chemistry triiodide (sometimes written tri-iodide can have several meanings This is also the formulation of some types of medicinal (antiseptic) iodine, although tincture of iodine classically dissolves the element in alcohol. Tincture of iodine is a disinfectant usually 8% elemental Iodine in Ethanol. The deep blue color of starch-iodine complexes is produced only by the free element. Starch, CAS # 9005-25-8 Chemical formula (C6H10O5n is a Polysaccharide

Students who have seen the classroom demonstration in which iodine crystals are gently heated in a test tube to violet vapor, may gain the impression that liquid iodine does not exist at atmospheric pressure. This misconception arises because the small amount of vapor produced has such a deep colour that the liquid appears not to form. In fact, if iodine crystals are heated carefully to just above their melting point of 113. 7 °C, the crystals melt into a liquid which is present under a dense blanket of the vapor.

History

Iodine was discovered by Bernard Courtois in 1811. Bernard Courtois, also spelled Barnard Courtois, ( 12 February 1777 &ndash 27 September 1838) was a French Chemist He was born to a manufacturer of saltpeter (a vital part of gunpowder). Potassium nitrate is a Chemical compound with the Chemical formula K[[Nitrogen N]] O 3 At the time of the Napoleonic Wars, France was at war and saltpeter was in great demand. The Napoleonic Wars (1803-1815 involved Napoleon's French Empire and a shifting set of European allies and opposing coalitions This article is about the country For a topic outline on this subject see List of basic France topics. Saltpeter produced from French niter beds required sodium carbonate, which could be isolated from seaweed washed up on the coasts of Normandy and Brittany. Niter (US or nitre (UK is the mineral form of Potassium nitrate, KNO3 also known as saltpeter (US or saltpetre (UK Seaweed is a loose colloquial term encompassing macroscopic Multicellular, benthic marine Algae. Normandy (Normandie Norman: Normaundie) is a geographical region corresponding to the former Duchy of Normandy. Brittany (Breizh bʁejs Bretagne; Gallo: Bertaèyn) is a former independent Celtic kingdom and Duchy, now incorporated into To isolate the sodium carbonate, seaweed was burned and the ash then washed with water. The remaining waste was destroyed by adding sulfuric acid. Sulfuric (or sulphuric acid, H 2 S[[oxygen O]]4 is a strong Mineral acid. One day Courtois added too much sulfuric acid and a cloud of purple vapor rose. Courtois noted that the vapor crystallized on cold surfaces making dark crystals. Courtois suspected that this was a new element but lacked the money to pursue his observations.

However he gave samples to his friends, Charles Bernard Desormes (1777 - 1862) and Nicolas Clément (1779 - 1841), to continue research. Charles Bernard Desormes ( 3 June 1771 - 30 August 1862) was a French physicist and chemist Nicolas Clément (1779 Dijon - 1842 was a French physicist and chemist. He also gave some of the substance to Joseph Louis Gay-Lussac (1778 - 1850), a well-known chemist at that time, and to André-Marie Ampère (1775 - 1836). Joseph Louis Gay-Lussac (also Louis Joseph Gay-Lussac, December 6, 1778 – May 9, 1850) was a French chemist André-Marie Ampère (20 January 1775 &ndash 10 June 1836 was a French Physicist and Mathematician who is generally credited as one of the main discoverers On 29 November 1813, Dersormes and Clément made public Courtois’ discovery. Events 1777 - San Jose California, is founded as el Pueblo de San José de Guadalupe Year 1813 ( MDCCCXIII) was a Common year starting on Friday (link will display the full calendar of the Gregorian calendar (or a Common They described the substance to a meeting of the Imperial Institute of France. On December 6, Gay-Lussac announced that the new substance was either an element or a compound of oxygen. Ampère had given some of his sample to Humphry Davy (1778 - 1829). Sir Humphry Davy 1st Baronet FRS MRIA (17 December 1778 &ndash 29 May 1829 was a British Chemist and inventor Davy did some experiments on the substance and noted its similarity to chlorine. Chlorine (ˈklɔriːn from the Greek word 'χλωρóς' ( khlôros, meaning 'pale green' is the Chemical element with Atomic number 17 and Davy sent a letter dated December 10 to the Royal Society of London stating that he had identified a new element. The Royal Society of London for the Improvement of Natural Knowledge, known simply as The Royal Society, is a Learned society for science that was founded in 1660 A large argument erupted between Davy and Gay-Lussac over who identified iodine first but both scientists acknowledged Courtois as the first to isolate the chemical element.

Applications

Iodine is used in pharmaceuticals, antiseptics, medicine, food supplements, dyes, catalysts, halogen lights, photography, water purifying, and starch detection.

• Tincture of iodine (10% elemental iodine in ethanol base) is an essential component of any emergency survival kit, used both to disinfect wounds and to sanitize surface water for drinking (3 drops per litre, let stand for 30 minutes). Tincture of iodine is a disinfectant usually 8% elemental Iodine in Ethanol. Alcohol-free iodine solutions such as Lugol's iodine, as well as other iodophor type antiseptics, are also available as effective elemental iodine sources for this purpose. Lugol's iodine, also known as Lugol's solution, first made in 1829 is a solution of elemental Iodine and potassium iodide in water named after the French An Iodophor is a preparation containing Iodine complexed with a solubilizing agent such as a surfactant or Povidone (forming Povidone-iodine
• Iodine compounds are important in the field of organic chemistry
• Iodine, as a heavy element, is quite radio-opaque. Organic chemistry is a discipline within Chemistry which involves the scientific study of the structure properties composition reactions, and preparation Radiopacity refers to the relative inability of electromagnetism to pass through a particular material particularly X-rays. Organic compounds of a certain type (typically iodine-substituted benzene derivatives) are thus used in medicine as X-ray radiocontrast agents for intravenous injection. Medicine is the art and science of healing It encompasses a range of Health care practices evolved to maintain and restore Human Health by the Contrast medium Radiocontrast agents (also simply contrast agents or contrast materials) are compounds used to improve the visibility of internal bodily structures This is often in conjunction with advanced X-ray techniques such as angiography and CT scanning
• Silver iodide is used in photography. Angiography or arteriography is a Medical imaging technique in which an X-ray image is taken to visualize the inside or lumen, of blood vessels Computed tomography (CT is a Medical imaging method employing Tomography. Silver iodide ( Ag[[Iodine I]] is a Chemical compound used in Photography and as an Antiseptic in medicine
• Tungsten iodide is used to stabilize the filaments in light bulbs. Tungsten (ˈtʌŋstən also known as wolfram (/ˈwʊlfrəm/ is a Chemical element that has the symbol W and Atomic number 74 The incandescent light bulb, incandescent lamp or incandescent light globe is a source of electric Light that works by Incandescence, (a general
• Iodine crystals are used in the process to make NI₃ or nitrogen triiodide. Nitrogen triiodide, also called nitrogen iodide, more correctly triiodine nitride, is the Chemical compound with the formula N[[Iodine I]]3 This compound is a shock-sensitive explosive when dry. It has commonly been used for pranks, but because of its extreme touch sensitivity, is not useful commercially.

Occurrence on earth

Iodine naturally occurs in the environment chiefly as dissolved iodide in seawater, although it is also found in some minerals and soils. An iodide Ion is an iodine atom with a &minus1 charge. Compounds with iodine in formal Oxidation state &minus1 are called iodides Seawater is Water from a Sea or Ocean. On average seawater in the world's oceans has a Salinity of about 3 The element may be prepared in an ultrapure form through the reaction of potassium iodide with copper(II) sulfate. Potassium iodide is an Inorganic compound with formula K[[iodide I]] Copper(II sulfate is the Chemical compound with the formula Cu[[Sulfur S]] O 4 There are also a few other methods of isolating this element in the laboratory-- for example the method used to isolate other halogens: oxidation of the iodide in hydroiodic acid (often made in situ with an iodide and sulfuric acid) by manganese dioxide (see below in Descriptive chemistry). Hydrogen iodide (HI is a Diatomic molecule. Aqueous solutions of HI are known as hydroiodic acid or hydriodic acid, a Strong acid. Manganese(IV oxide is the Chemical compound MnO2 commonly called manganese dioxide. Although the element is actually quite rare, kelp and certain plants and algae have some ability to concentrate iodine, which helps introduce the element into the food chain. Kelp are large Seaweeds ( Algae) belonging to the Brown algae and classified in the order Laminariales Algae ( sing. alga are a large and diverse group of simple typically Autotrophic organisms ranging from Unicellular to Multicellular forms Food chains, also called food networks and/or trophic networks, describe the feeding relationships between species within an Ecosystem.

Sources

Iodine is found in the mineral caliche, found in Chile, between the Andes and the sea. Caliche is a hardened deposit of Calcium carbonate. This calcium carbonate cements together other materials including gravel sand clay and silt Chile, officially the Republic of Chile ( Spanish:) is a country in South America occupying a long and narrow Coastal strip wedged between the The Andes form the world's longest exposed Mountain range. They lie as a continuous chain of highland along the western coast of South America. It can also be found in some seaweeds as well as extracted from seawater.

Extraction from seawater involves electrolysis. The brine is first purified and acidified using sulphuric acid and is then reacted with chlorine. An iodine solution is produced but it is yet too dilute and has to be concentrated. To do this air is blown into the solution which causes the iodine to evaporate, then it is passed into an absorbing tower containing acid where sulfur dioxide is added to reduce the iodine. The solution is then added to chlorine again to concentrate the solution more, and the final solution is at a level of about 99%.

Another source is from kelp. Kelp are large Seaweeds ( Algae) belonging to the Brown algae and classified in the order Laminariales This source was used in the 18th and 19th centuries but is no longer economically viable.

In 2005, Chile was the top producer of iodine with almost two-thirds world share followed by Japan and the USA, reports the British Geological Survey. The British Geological Survey (BGS is a partly publicly-funded body which aims to advance geoscientific knowledge of the United Kingdom landmass and its Continental

Descriptive chemistry

Elemental iodine is poorly soluble in water, with one gram dissolving in 3450 ml at 20 °C and 1280 ml at 50 °C. By contrast with chlorine, the formation of the hypohalite ion (IO^–) in neutral aqueous solutions of iodine is negligible. Chlorine (ˈklɔriːn from the Greek word 'χλωρóς' ( khlôros, meaning 'pale green' is the Chemical element with Atomic number 17 and

I₂+ H₂O ↔ H⁺ + I^– + HIO   (K = 2. 0×10⁻¹³)^[1]

Solubility in water is greatly improved if the solution contains dissolved iodides such as hydroiodic acid, potassium iodide, or sodium iodide; this extra solubility results from the high solubility of the I₃^- ion. An iodide Ion is an iodine atom with a &minus1 charge. Compounds with iodine in formal Oxidation state &minus1 are called iodides Hydrogen iodide (HI is a Diatomic molecule. Aqueous solutions of HI are known as hydroiodic acid or hydriodic acid, a Strong acid. Potassium iodide is an Inorganic compound with formula K[[iodide I]] Sodium iodide is a white Crystalline Salt with Chemical formula Na[[Iodine I]] used in radiation detection treatment of Iodine deficiency Dissolved bromides also improve water solubility of iodine. A bromide Ion is a Bromine atom with charge of −1 Compounds with bromine in formal Oxidation state −1 are called bromides Iodine is soluble in a number of organic solvents, including ethanol (20. 5 g/100 ml at 15 °C, 21. 43 g/100 ml at 25 °C), diethyl ether (20. Diethyl ether, also known as ether and ethoxyethane, is a clear colorless and highly Flammable liquid with a low Boiling point and a 6 g/100 ml at 17 °C, 25. 20 g/100 ml at 25 °C), chloroform, acetic acid, glycerol, benzene (14. Chloroform, also known as trichloromethane and methyl trichloride, is a Chemical compound with formula C[[Hydrogen H]] Cl Acetic acid, also known as ethanoic acid, is an organic chemical compound, giving Vinegar its sour taste Benzene, or benzol, is an organic Chemical compound and a known Carcinogen with the molecular formula C 6 H 6 09 g/100 ml at 25 °C), carbon tetrachloride (2. Carbon tetrachloride, also known by many other names (see Table is the Organic compound with the formula CCl4 603 g/100 ml at 35 °C), and carbon disulfide (16. 47 g/100 ml at 25 °C). ^[2] Aqueous and ethanol solutions are brown. Solutions in chloroform, carbon tetrachloride, and carbon disulfide are violet.

Elemental iodine can be prepared by oxidizing iodides with chlorine:

2I^– + Cl₂ → I₂ + 2Cl^–

or with manganese dioxide in acid solution:^[1]

2I^– + 4H⁺ + MnO₂ → I₂ + 2H₂O + Mn²⁺

Iodine is reduced to hydroiodic acid by hydrogen sulfide:^[3]

I₂ + H₂S → 2HI + S↓

or by hydrazine:

2I₂ + N₂H₄ → 4HI + N₂

Iodine is oxidized to iodate by nitric acid:^[4]

I₂ + 10HNO₃ → 2HIO₃ + 10NO₂ + 4H₂O

or by chlorates:^[4]

I₂ + 2ClO₃^– → 2IO₃^– + Cl₂

Iodine is converted in a two stage reaction to iodide and iodate in solutions of alkali hydroxides (such as sodium hydroxide):^[1]

I2 + 2OH– → I– + IO– + H2O		(K = 30)
3IO– → 2I– + IO3–		(K = 1020)

Notable inorganic iodine compounds

See also iodine compounds

Stable iodine in biology

Iodine is an essential trace element, the heaviest-known element needed by living organisms. An iodide Ion is an iodine atom with a &minus1 charge. Compounds with iodine in formal Oxidation state &minus1 are called iodides Manganese(IV oxide is the Chemical compound MnO2 commonly called manganese dioxide. Hydrogen iodide (HI is a Diatomic molecule. Aqueous solutions of HI are known as hydroiodic acid or hydriodic acid, a Strong acid. Hydrogen sulfide (or hydrogen sulphide) is the Chemical compound with the formula H 2 S. Hydrazine is a Chemical compound with the formula N2H4 It has an Ammonia -like odor and is derived from the same industrial chemistry An iodate is a Salt of Iodic acid. In the iodate Anion, Iodine is bonded to three Oxygen atoms and the Molecular formula Nitric acid ( H[[nitrate NO3]] also known as Aqua fortis and spirit of nitre, is a highly corrosive and The chlorate anion has the formula ClO3− In this case the Chlorine atom is in the +5 Oxidation state. An iodide Ion is an iodine atom with a &minus1 charge. Compounds with iodine in formal Oxidation state &minus1 are called iodides An iodate is a Salt of Iodic acid. In the iodate Anion, Iodine is bonded to three Oxygen atoms and the Molecular formula Sodium hydroxide ( Na[[hydroxide OH]]) also known as Lye, caustic soda and (incorrectly according to IUPAC nomenclature Hydrogen iodide (HI is a Diatomic molecule. Aqueous solutions of HI are known as hydroiodic acid or hydriodic acid, a Strong acid. Lithium iodide, or LiI is a compound of Lithium and Iodine. When exposed to Air, it becomes yellow in color due to the Oxidation Beryllium iodide is the Chemical compound with the formula BeI2 Boron triiodide is a Chemical compound of Boron and Iodine with Chemical formula BI3 Carbon tetraiodide is CI4, a Tetrahalomethane. Being bright red it is a relatively rare example of a highly colored methane derivative Nitrogen triiodide, also called nitrogen iodide, more correctly triiodine nitride, is the Chemical compound with the formula N[[Iodine I]]3 Iodine oxides are Chemical compounds and Oxides of Iodine. There exist multiple oxides as iodine has more than one Oxidation state. Iodine pentoxide is the Chemical compound with the formula I2O5 Iodine oxides are Chemical compounds and Oxides of Iodine. There exist multiple oxides as iodine has more than one Oxidation state. Iodine pentafluoride, IF5 is a Fluoride of Iodine. It is a colourless or yellow liquid with a density of 3250 kg m−3 Iodine heptafluoride, also known as iodine(VII fluoride or even iodine fluoride is the compound I[[fluoride F]]7 Sodium iodide is a white Crystalline Salt with Chemical formula Na[[Iodine I]] used in radiation detection treatment of Iodine deficiency Magnesium iodide is the name for the Chemical compounds with the formulas MgI2 and its various hydrates MgI2(H2Ox Aluminium iodide is any Chemical compound containing only Aluminium and Iodine. Silicon tetraiodide is the Chemical compound with the formula Si[[Iodine I4]] Phosphorus triiodide (PI3 is an unstable red solid which reacts violently with water Iodine monochloride is the Chemical compound with the formula ICl Iodine trichloride is a compound of Iodine and Chlorine. It is bright yellow and in the solid state is present as a planar dimer I2Cl6 Potassium iodide is an Inorganic compound with formula K[[iodide I]] Calcium iodide (CaI2 is an ionic compound of Calcium and Iodine. Titanium tetraiodide is the Inorganic compound with the formula TiI4 Nickel iodide is an Inorganic compound with the formula NiI2 This paramagnetic bluish-black solid dissolves readily in water to give blue-green solutions Copper(I iodide is the Chemical compound with the formula CuI it is also known as cuprous iodide. Zinc iodide is composed of Zinc and Iodine. It is an Inorganic compound with a Molecular weight of 319 Gallium(III iodide is the Chemical compound with the formula Ga 2 I6. Germanium iodide is a Chemical compound of Germanium and Iodine. Germanium iodide is a Chemical compound of Germanium and Iodine. Rubidium iodide is a compound with a Melting point of 642 degrees Celsius. Strontium iodide (SrI2 is a Salt of Strontium and Iodine. It is an ionic water-soluble and Deliquescent compound that can Zirconium(IV iodide is the Chemical compound with the formula Zr[[Iodine I4]] Silver iodide ( Ag[[Iodine I]] is a Chemical compound used in Photography and as an Antiseptic in medicine Cadmium iodide, CdI2 is a chemical compound of Cadmium and Iodine. There are three sets of indium halides, the trihalides the monohalides and a surprising number of intermediate halides Tin(IV iodide, also known as stannic iodide is the Chemical compound with the formula SnI4 Tin(II iodide, also known as stannous iodide, is an ionic compound of Tin and Iodine with the formula SnI2 Antimony triiodide is the Chemical compound with the formula Sb[[Iodine I3]] Tellurium tetraiodide ( Te[[Iodine I4]] is an Inorganic Chemical compound. Caesium iodide (CsI is an Ionic compound often used as the input Phosphor of an X-ray image intensifier tube found in Fluoroscopy equipment Barium iodide occurs in two forms one anhydrous and the other hydrated Gold halides are compounds of Gold with the Halogens Monohalides AuCl, AuBr, and AuI are all crystalline solids with Mercury(II iodide ( Hg[[Iodine I2]] is a Chemical compound with an appearance of red-orange crystals Thallium(I iodide ( Tl[[Iodine I]] is a Chemical compound of formula TlI Lead (II iodide ( Pb[[iodine I]]2 is a toxic yellowish solid It displays a range of colors with varying temperature from bright yellow at room temperature to brick Samarium(II iodide (SmI2 is a green solid composed of Samarium and Iodine, with a melting point of 520 °C where the samarium atom has a coordination Terbium(III iodide ( Tb[[Iodine I3]] is an Inorganic Chemical compound. Thorium(IV iodide ( Th[[Iodine I4]] is an Inorganic Chemical compound. In Analytical chemistry, a trace element is an element in a sample that has an average Concentration of less than 100 Parts per million atoms Its only known roles in animal biology are as constituents of the thyroid hormones, thyroxine (T4) and triiodothyronine (T3). The thyroid is one of the largest Endocrine glands in the body Hormones (from Greek ὁρμή - "impetus" are chemicals released by cells that affect cells in other parts of the body Thyroxine, or 353'5'-tetra­iodothyronine (often abbreviated as T4) a form of Thyroid hormones is the major Hormone secreted by the Triiodothyronine, C15[[hydrogen H12]] I3[[nitrogen N]] O4, also known as T3, is a Thyroid These are made from addition condensation products of the amino acid tyrosine, and are stored prior to release in a protein-like iodine-containing molecule called thyroglobulin. Tyrosine (abbreviated as Tyr or Y) or 4-hydroxyphenylalanine, is one of the 20 Amino acids that are used by cells to synthesize Thyroglobulin (Tg is a 660 kDa dimeric Protein produced by and used entirely within the Thyroid gland 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. The thyroid is one of the largest Endocrine glands in the body Thyroid hormones are phylogenetically very old molecules which are synthesized by most multicellular organisms, and which even have some effect on unicellular organisms.

Thyroid hormones play a very basic role in biology, acting on gene transcription to regulate the basal metabolic rate. Basal metabolic rate ( BMR) is the amount of energy expended while at rest in a neutrally temperate environment in the post-absorptive state (meaning that the digestive system The total deficiency of thyroid hormones can reduce basal metabolic rate up to 50%, while in excessive production of thyroid hormones the basal metabolic rate can be increased by 100%. T4 acts largely as a precursor to T3, which is (with some minor exceptions) the biologically active hormone.

Human dietary intake

The United States Food and Drug Administration recommends 150 micrograms of iodine per day for both men and women. ^[5] This is necessary for proper production of thyroid hormone. ^[5] Natural sources of iodine include sea life, such as kelp and certain seafood, as well as plants grown on iodine-rich soil. ^[6][7] Salt for human consumption is often fortified with iodine and is referred to as iodized salt. ^[7]

Iodine deficiency

Main article: Iodine deficiency

In areas where there is little iodine in the diet—typically remote inland areas and semi-arid equatorial climates where no marine foods are eaten—iodine deficiency gives rise to hypothyroidism, symptoms of which are extreme fatigue, goitre, mental slowing, depression, weight gain, and low basal body temperatures. Iodine is an essential Trace element; the Thyroid hormones Thyroxine and Triiodotyronine contain iodine Iodine is an essential Trace element; the Thyroid hormones Thyroxine and Triiodotyronine contain iodine A goitre ( BrE) or goiter ( AmE) ( Latin struma) also called a bronchocele, is a swelling in the neck (just below the

Iodine deficiency is also the leading cause of preventable mental retardation, a result which occurs primarily when babies or small children are rendered hypothyroidic by a lack of the element. Mental retardation is a generalized triarchic disorder characterized by subaverage cognitive functioning and deficits in two or more adaptive behaviors with onset before the age Hypothyroidism is the disease state in humans and animals caused by insufficient production of Thyroid hormone by the Thyroid gland. The addition of iodine to table salt has largely eliminated this problem in the wealthier nations, but as of March 2006, iodine deficiency remained a serious public health problem in the developing world. ^[8]

Radioiodine and biology

Radioiodine and the thyroid

Human exposure to radioactive iodine will cause thyroid uptake, as with all iodine, leading to elevated chances of thyroid cancer. Isotopes with shorter half-lives such as I¹³¹ present a greater risk than those with longer half-lives since they generate more radiation per unit of time. Taking large amounts of regular iodine will saturate the thyroid and prevent uptake. Iodine pills are sometimes distributed to persons living close to nuclear establishments, for use in case of accidents that could lead to releases of radioactive iodine.

• Iodine-123 and iodine-125 are used in medicine as tracers for imaging and evaluating the function of the thyroid. Iodine-123 (123I is a radioactive Isotope of Iodine used in Nuclear medicine imaging including Single photon Iodine-125 (125I is a Radioisotope of Iodine which has uses in Biological assays and in Radiation therapy to treat Prostate cancer
• Uncombined (elemental) iodine is mildly toxic to all living things.

The artificial radioisotope ¹³¹I (a beta emitter), has a half-life of 8. A radionuclide is an Atom with an unstable nucleus, which is a nucleus characterized by excess energy which is available to be imparted either to a newly-created In Nuclear physics, beta decay is a type of Radioactive decay in which a Beta particle (an Electron or a Positron) is emitted Half-Life (computer-game page here It's already listed in the disambiguation page 0207 days. Also known as radioiodine, ¹³¹I has been used in treating cancer and other pathologies of the thyroid glands. Iodine-131 (131I, also called radioiodine, is a Radioisotope of Iodine which has medical and pharmaceutical uses Cancer (medical term Malignant Neoplasm) is a class of Diseases in which a group of cells display uncontrolled The thyroid is one of the largest Endocrine glands in the body A gland is an organ in an animal's body that synthesizes a substance for release such as Hormones or Breast milk, often into the Bloodstream ¹²³I is the radioisotope most often used in nuclear imaging of the kidney and thyroid as well as thyroid uptake scans (used for the evaluation of Graves' Disease). The kidneys are complicated organs that have numerous biological roles Graves' disease is a Thyroid disorder characterized by goiter, Exophthalmos, "orange-peel" skin and Hyperthyroidism. The most common compounds of iodine are the iodides of sodium and potassium (KI) and the iodates (KIO₃). Sodium (ˈsoʊdiəm is an element which has the symbol Na( Latin natrium, from Arabic natrun) atomic number 11 atomic mass 22 Potassium (pəˈtæsiəm is a Chemical element. It has the symbol K (kalium from qalīy Atomic number 19 and Atomic mass 39 Potassium iodide is an Inorganic compound with formula K[[iodide I]]

Potassium iodide (KI tablets, or "SSKI" = "Saturated Solution of KI" liquid drops) can be given to people in a nuclear disaster area when fission has taken place, to block the uptake of iodine-131 by the thyroid. Potassium iodide is an Inorganic compound with formula K[[iodide I]] Nuclear fission is the splitting of the nucleus of an atom into parts (lighter nuclei) often producing Free neutrons and other smaller nuclei which may The protective effect of KI lasts approximately 24 hours, so it should be dosed daily until a risk of significant exposure to radioiodines no longer exists. ^[9][10] The exposure can be reduced by evacuation, sheltering, and by control of the food supply. Iodine-131 also decays rapidly, with a half-life of 8 days, so that 99. 95% of the original radioiodine is gone after three months.

Iodine-129 ¹²⁹I (half-life 15. Iodine-129 (129I is a Radioisotope of Iodine. Formation and decay 129I is primarily formed from the Fission Half-Life (computer-game page here It's already listed in the disambiguation page 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 and uranium and plutonium fission, both in subsurface rocks and nuclear reactors. Cosmic ray spallation is a form of naturally occurring Nuclear fission and Nucleosynthesis. Xenon (ˈzɛnɒn or) is a Chemical element represented by the symbol Xe. Temperature and layers The temperature of the Earth's atmosphere varies with altitude the mathematical relationship between temperature and altitude varies among five For the 1962 Bruce Conner film see Cosmic Ray (film Cosmic rays are energetic particles originating from space that impinge on The muon (from the letter mu (μ--used to represent it is an Elementary particle with negative Electric charge and a spin of 1/2 Uranium (jʊˈreɪniəm is a silvery-gray Metallic Chemical element in the Nuclear processes, in particular nuclear fuel reprocessing and atmospheric nuclear weapons tests have now swamped the natural signal for this isotope. ¹²⁹I was used in rainwater studies following the Chernobyl accident. The Chernobyl disaster was a nuclear reactor accident in the Chernobyl Nuclear Power Plant in the Soviet Union. It also has been used as a ground-water tracer and as an indicator of nuclear waste dispersion into the natural environment.

Radioiodine and the kidney

In the 1970s imaging techniques were developed in California to utilize radioiodine in diagnostics for renal hypertension. California ( is a US state on the West Coast of the United States, along the Pacific Ocean. The kidneys are complicated organs that have numerous biological roles Hypertension, also referred to as high blood pressure, HTN or HPN, is a medical condition in which the Blood pressure is chronically elevated

Isotopes

Main article: isotopes of iodine

There are 37 isotopes of iodine and only one, ¹²⁷I, is stable. There are 37 Isotopes of Iodine ( I) and only one 127I is stable Isotopes (Greek isos = "equal" tópos = "site place" are any of the different types of atoms ( Nuclides

In many ways, ¹²⁹I is similar to ³⁶Cl. Chlorine-36 is an Isotope of Chlorine. Chlorine has two Stable isotopes and one Radioactive environmental isotope: the cosmogenic isotope 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. An ion is an Atom or Molecule which has lost or gained one or more Valence electrons giving it a positive or negative electrical charge 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 half-life 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. An ion is an Atom or Molecule which has lost or gained one or more Valence electrons giving it a positive or negative electrical charge An iodate is a Salt of Iodic acid. In the iodate Anion, Iodine is bonded to three Oxygen atoms and the Molecular formula This makes it fairly easy for ¹²⁹I to enter the biosphere as it becomes incorporated into vegetation, soil, milk, animal tissue, etc.

Excesses of stable ¹²⁹Xe in meteorites have been shown to result from decay of "primordial" Iodine-129 produced newly by the supernovas which created the dust and gas from which the solar system formed. Iodine-129 (129I is a Radioisotope of Iodine. Formation and decay 129I is primarily formed from the Fission ¹²⁹I was the first extinct radionuclide to be identified as present in the early solar system. An extinct Radionuclide is one which was thought to have been formed by a primordial process such as stellar Nucleogenesis in the Supernova (s which contributed The Solar System consists of the Sun and those celestial objects bound to it by Gravity. Its decay is the basis of the I-Xe Iodine-xenon radiometric dating scheme, which covers the first 83 million years of solar system evolution. Radiometric dating (often called radioactive dating) is a technique used to date materials usually based on a comparison between the observed abundance of a naturally occurring The Solar System consists of the Sun and those celestial objects bound to it by Gravity.

Effects of various radioiodine isotopes in biology are discussed above. Iodine (ˈaɪədaɪn ˈaɪədɪn or /ˈaɪədiːn/ from ιώδης iodes "violet" is a Chemical element that has the symbol I and Atomic

Toxicity of iodine

Excess iodine has symptoms similar to those of iodine deficiency. Commonly encountered symptoms are abnormal growth of the thyroid gland and disorders in functioning and growth of the organism as a whole. Elemental iodine, I₂, is a deadly poison if taken in larger amounts; if 2-3 grams of it is consumed, it is fatal to humans. Iodides are similar in toxicity to bromides.

Precautions for stable iodine

Direct contact with skin can cause lesions, so it should be handled with care. Iodine vapor is very irritating to the eye and to mucous membranes. Eyes are organs that detect Light, and send signals along the Optic nerve to the visual areas of the brain Concentration of iodine in the air should not exceed 1 mg/m³ (eight-hour time-weighted average). For other uses of the words gram or gramme see Gram (disambiguation. CM3 redirects here If you were looking for the 3rd game in the Cooking Mama series abbreviated as CM3 see here. When mixed with ammonia, it can form nitrogen triiodide which is extremely sensitive and can explode unexpectedly. Ammonia is a compound with the formula N[[hydrogen H3]] It is normally encountered as a Gas with a characteristic pungent Odor Nitrogen triiodide, also called nitrogen iodide, more correctly triiodine nitride, is the Chemical compound with the formula N[[Iodine I]]3

Clandestine use

In the United States, the Drug Enforcement Agency (DEA) regards iodine and compounds containing iodine (ionic iodides, iodoform, ethyl iodide, and so on) as reagents useful for the clandestine manufacture of methamphetamine. The Drug Enforcement Administration ( DEA) is a United States Department of Justice Law enforcement agency tasked with combating drug smuggling and Persons who attempt to purchase significant quantities of such chemicals without establishing a legitimate use are likely to find themselves the target of a DEA investigation. Persons selling such compounds without doing due diligence to establish that the materials are not being diverted to clandestine use may be subject to stiff penalties, such as expensive fines or even imprisonment. Due Diligence is a term used for a number of concepts involving either the performance of an investigation of a business or person or the performance of an act with a certain Standard ^[11][12]

See also

• Iodide as an antioxidant
• Iodised salt
• Chemical Oxygen Iodine Laser
• Nutrition facts label

References

External links

• "Micronutrient Research for Optimum Health", Linus Pauling Institute, OSU Oregon State University
• ATSDR - CSEM: Radiation Exposure from Iodine 131 U. S. Department of Health and Human Services (public domain)
• ChemicalElements.com - Iodine
• who.int - WHO Global Database on Iodine Deficiency
• Network for Sustained Elimination of Iodine Deficiency
• Oxidizing Agents > Iodine
• Los Alamos National Laboratory - Iodine

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