Iodine Elemental Symbol

French German Italian Portuguese Spanish Swedish
L'iode Jod Iodio Iodo Yodo Jod

Iodine(I) atomic and molecular weight, atomic number and elemental symbol Iodine is a Block P, Group 17, Period 5 element. Elemental IodineThe number of electrons in each of Iodine's shells is 2, 8, 18, 18, 7 and its electron configuration is [Kr] 4d10 5s2 5p5. Iodine Bohr ModelThe iodine atom has a radius of and it's Van der Waals radius is In its elemental form, CAS 7553-56-2, iodine has a lustrous metallic gray appearance as a solid. As a gas it has a violet appearance. Iodine is found mainly as the highly water-soluble iodide I-. Iodine was discovered and first isolated by Bernard Courtois in 1811.

Iodine forms compounds with many elements, but is less active than the other halogens. Iodine is only slightly soluble in water. It dissolves readily in chloroform, carbon tetrachloride, or carbon disulfide to form purple solutions. Iodine compounds are important in organic chemistry and very useful in medicine. Potassium iodide is used in photography. Iodine is available as compounds with purities from 99% to 99.999% (ACS grade to ultra-high purity). Elemental or metallic forms include pellets, rod, wire and granules for evaporation source material purposes. Oxides are available in powder and dense pellet form for such uses as optical coating and thin film applications. Oxides tend to be insoluble. Fluorides are another insoluble form for uses in which oxygen is undesirable such as metallurgy, chemical and physical vapor deposition and in some optical coatings. Iodine is also available in soluble forms including chlorides, nitrates and acetates. These compounds can be manufactured as solutions at specified stoichiometries.

Iodine in large amounts is poisonous but in small doses is only slightly toxic. Safety data for Iodine and its compounds can vary widely depending on the form. For potential hazard information, toxicity, and road, sea and air transportation limitations, such as DOT Hazard Class, DOT Number, EU Number, NFPA Health rating and RTECS Class, please see the specific material or compound referenced in the Products tab below.

  • Properties
  • Safety Data
  • Products
  • Research
  • Isotopes
  • Other Elements

Iodine Properties

Symbol: I Melting Point: 113.7 oC, 236.66 oF, 386.85 K
Atomic Number: 53 Boiling Point: 184.4 oC, 363.92 oF, 457.55 K
Atomic Weight: 126.9 Density: 4953 kg m-3
Element Category: halogen Liquid Density @ Melting Point: N/A
Group, Period, Block: 17 (halogens), 5, p Specific Heat: N/A
    Heat of Vaporization 41.57 kJ mol-1 of I2
CHEMICAL STRUCTURE Heat of Fusion 15.52 kJ mol-1 of I2
Electrons: 53 Thermal Conductivity: 0.449 W·m−1·K−1
Protons: 53 Thermal Expansion: N/A
Neutrons: 74 Electrical Resistivity: (0 °C) 1.3×107Ω·m
Electron Configuration: [Kr]5s24d105p5 Electronegativity: 2.66 (Pauling scale)
Atomic Radius: 140 pm Tensile Strength: N/A
Covalent Radius: 139±3 pm Molar Heat Capacity: (I2) 54.44 J·mol−1·K−1
Van der Waals radius: 198 pm Young's Modulus: N/A
Oxidation States: 5, 7, -1 Shear Modulus: N/A
Phase: Solid Bulk Modulus: 7.7 GPa
Crystal Structure: orthorhombic Poisson Ratio: N/A
Magnetic Ordering: diamagnetic Mohs Hardness: N/A
1st Ionization Energy: 1008.4 kJ mol-1 Vickers Hardness: N/A
2nd Ionization Energy: 1845.8 kJ mol-1 Brinell Hardness: N/A
3rd Ionization Energy: 3184 kJ mol-1 Speed of Sound: N/A
CAS Number: 7553-56-2 Abundance in typical human body, by weight: 200 ppb
ChemSpider ID: 4514549 Abundance in typical human body, by atom: 10 atoms relative to C = 1000000
PubChem CID: 807 Abundance in universe, by weight: 1 ppb
MDL Number: MFCD00011355 Abundance in universe, by atom: 0.01 ppb
EC Number: 231-442-4 Discovered By: Bernard Courtois
Beilstein Number: 3587194 Discovery Date: 1811
SMILES Identifier: [I]  
InChI Identifier: InChI=1S/I Other Names: Jod, Iodio

Iodine Products


Aluminum Iodide
Aluminum Iodide, Ultra Dry
Americium Iodide
Ammonium Iodide
Antimony(III) Iodide
Antimony Iodide, Ultra Dry
Arsenic Diiodide
Arsenic(III) Iodide
Barium Iodide
Barium Iodide, Ultra Dry
Beryllium Iodide
Bismuth Iodide
Bismuth Iodide, Ultra Dry
Bismuth Oxyiodide
Bis(cyclopentadienyl) Vanadium(III) Iodide
Boron Iodide
Cadmium Iodide
Cadmium Iodide, Ultra Dry
Calcium Iodide
Calcium Iodide, Ultra Dry
Cerium(II) Iodide
Cerium(III) Iodide
Cerium Iodide, Ultra Dry
Cesium Dichloroiodide
Cesium Iodide
Cesium Iodide Windows
Cesium Iodide, Thallium doped
Cesium Triiodide
Cesium Iodide, Ultra Dry
Chromium(II) Iodide
Chromium(III) Iodide
Cobalt(II) Iodide
Cobalt(II) Iodide, Ultra Dry
Copper(I) Iodide
Copper(I) Iodide/Cesium Carbonate Admixture
Copper(I) Iodide Trimethylphosphite Complex
Copper(I) Mercury Iodide
Dysprosium(II) Iodide
Dysprosium(III) Iodide
Dysprosium(III) Iodide, Ultra Dry
Erbium Iodide
Erbium Iodide, Ultra Dry
Europium(II) Iodide
Europium(III) Iodide
Gadolinium(III) Iodide
Gadolinium(III) Iodide, Ultra Dry
Gallium(III) Iodide
Gallium Iodide, Ultra Dry
Germanium(II) Iodide
Germanium(IV) Iodide
Gold(I) Iodide
Gold(III) Iodide
Gold Triiodide
Hafnium(III) Iodide
Hafnium(IV) Iodide
Hafnium(IV) Iodide, Ultra Dry
Hexaamminenickel(II) Iodide
Holmium Iodide
Holmium Iodide, Ultra Dry
Indium(I) Iodide
Indium(III) Iodide
Indium(I) Iodide, Ultra Dry
Iridium(III) Iodide
Iridium(IV) Iodide
Iron(II) Iodide
Iron(II) Iodide, Ultra Dry
Lanthanum Iodide
Lanthanum Iodide, Ultra Dry
Lead(II) Iodide
Lead Iodide, Ultra Dry
Lithium Iodide
Lithium Iodide Hydrate
Lithium Iodide Trihydrate
Lithium Iodide, Ultra Dry
Lutetium Iodide
Lutetium Iodide, Ultra Dry
Magnesium Iodide
Magnesium Iodide, Ultra Dry
Manganese(II) Iodide
Manganese(II) Iodide Tetrahydrate
Manganese(II) Iodide, Ultra Dry
Mercuric Potassium Iodide
Mercury(I) Iodide
Mercury(I) Iodide Yellow
Mercury(II) Iodide
Mercury(II) Iodide, Ultra Dry
Mercury(II) Silver Iodide
Molybdenum(II) Iodide
Molybdenum(III) Iodide
Molybdenum(IV) Iodide
Neodymium(II) Iodide
Neodymium(III) Iodide
Nickel(II) Iodide
Nickel Iodide, Ultra Dry
Niobium(III) Iodide
Niobium(IV) Iodide
Niobium(V) Iodide
Osmium Zinc Iodide
Palladium(II) Iodide
Phosphorus(III) Iodide
Platinum(II) Iodide
Platinum(IV) Iodide
Potassium Hexaiodorhenate(IV)
Potassium Iodide
Potassium Iodide, Ultra Dry
Praseodymium(II) Iodide
Praseodymium(III) Iodide
Praseodymium(III) Iodide, Ultra Dry
Rhenium(III) Iodide
Rhodium(III) Iodide
Rubidium Iodide
Ruthenium(III) Iodide
Ruthenium(III) Iodide Hydrate
Samarium(II) Iodide
Samarium(III) Iodide
Samarium Iodide, Ultra Dry
Scandium Iodide
Scandium Iodide, Ultra Dry
Silicon Iodide
Silver(I) Iodide
Silver Potassium Iodide
Sodium Iodide
Sodium Iodide, Ultra Dry
Sodium Iodide, Thallium doped
Sodium Iodide Dihydrate
Strontium Iodide
Tantalum(IV) Iodide
Tantalum(V) Iodide
Tellurium Iodide
Terbium(III) Iodide
Terbium Iodide, Ultra Dry
Thallium Bromide/Iodide KRS-5
Thallium Iodide
Thallium(I) Iodide
Thallium Iodide, Ultra Dry
Thorium(IV) Iodide
Thulium(III) Iodide
Thulium Iodide, Ultra Dry
Tin(II) Iodide
Tin(IV) Iodide
Tin Iodide, Ultra Dry
Titanium(II) Iodide
Titanium(III) Iodide
Titanium(IV) Iodide
Titanium Iodide, Ultra Dry
Tungsten(II) Iodide
Tungsten(III) Iodide
Tungsten(IV) Iodide
Uranium(III) Iodide
Uranium(IV) Iodide
Vanadium(II) Iodide
Vanadium(III) Iodide
Ytterbium(II) Iodide
Ytterbium(III) Iodide
Yttrium Iodide
Yttrium Iodide, Ultra Dry
Zinc Iodide
Zinc Iodide, Ultra Dry
Zirconium(II) Iodide
Zirconium(III) Iodide
Zirconium(IV) Iodide

Recent Research & Development for Iodine

  • Abdullah M. Al-Hamdi, Mika Sillanpää, Joydeep Dutta, Photocatalytic degradation of phenol by iodine doped tin oxide nanoparticles under UV and sunlight irradiation, Journal of Alloys and Compounds, Volume 618, 5 January 2015
  • David A. McKeown, Isabelle S. Muller, Ian L. Pegg, Iodine valence and local environments in borosilicate waste glasses using X-ray absorption spectroscopy, Journal of Nuclear Materials, Volume 456, January 2015
  • Xiaodong Li, Bo Xu, Long Zhang, Fenfen Duan, Xinlin Yan, Jianqing Yang, Yongjun Tian, Synthesis of iodine filled CoSb3 with extremely low thermal conductivity, Journal of Alloys and Compounds, Volume 615, 5 December 2014
  • Mi-Hee Jung, Polypyrrole/poly(vinyl alcohol-co-ethylene) quasi-solid gel electrolyte for iodine-free dye-sensitized solar cells, Journal of Power Sources, Volume 268, 5 December 2014
  • Cem Göl, Mustafa Malkoç, Serkan Yeşilot, Mahmut Durmuş, Novel zinc(II) phthalocyanine conjugates bearing different numbers of BODIPY and iodine groups as substituents on the periphery, Dyes and Pigments, Volume 111, December 2014
  • Zengqiang Wang, Fengting Sang, Yuelong Zhang, Xiaokang Hui, Mingxiu Xu, Peng Zhang, Weili Zhao, Benjie Fang, Liping Duo, Yuqi Jin, An experimental research on the mixing process of supersonic oxygen–iodine parallel streams, Optics & Laser Technology, Volume 64, December 2014
  • Jakub Drnec, David A. Harrington, Oxygen and iodine adsorption on cesium-precovered Pt(111), Surface Science, Volume 630, December 2014
  • Luciano Canovese, Fabiano Visentin, Cladio Santo, Attack of molecular iodine to novel palladacyclopentadienyl complexes bearing isocyanides as spectator ligands. A computational and mechanistic study, Journal of Organometallic Chemistry, Volume 770, 1 November 2014
  • Zhi Ying, Yanwei Zhang, Shaojie Xu, Junhu Zhou, Jianzhong Liu, Zhihua Wang, Kefa Cen, Equilibrium potential for the electrochemical Bunsen reaction in the sulfur–iodine cycle, International Journal of Hydrogen Energy, Available online 5 October 2014
  • Rummana Matin, A.H. Bhuiyan, Changes in the optical properties of as-deposited plasma polymerized 2,6-diethylaniline thin films by iodine doping, Journal of Physics and Chemistry of Solids, Volume 75, Issue 10, October 2014

Iodine Isotopes

Iodine has one stable isotope: 127I.

Nuclide Symbol Isotopic Mass Half-Life Nuclear Spin
127I 126.904473 Stable 5/2+