Buy Iodine Cas 7553-56-2

Buy Iodine Cas 7553-56-2

Iodine is a chemical element; it has symbol I and atomic number 53. The heaviest of the stable halogens, it exists at standard conditions as a semi-lustrous, non-metallic solid that melts to form a deep violet liquid at 114 °C (237 °F), and boils to a violet gas at 184 °C (363 °F). The element was discovered by the French chemist Bernard Courtois in 1811 and was named two years later by Joseph Louis Gay-Lussac, after the Ancient Greek Ιώδης, meaning ‘violet’. Buy Iodine Cas 7553-56-2

Iodine occurs in many oxidation states, including iodide (I⁻), iodate (IO⁻
₃), and the various periodate anions. As the heaviest essential mineral nutrient, iodine is required for the synthesis of thyroid hormones.^[10] Iodine deficiency affects about two billion people and is the leading preventable cause of intellectual disabilities.^[11]

The dominant producers of iodine today are Chile and Japan. Due to its high atomic number and ease of attachment to organic compounds, it has also found favour as a non-toxic radiocontrast material. Because of the specificity of its uptake by the human body, radioactive isotopes of iodine can also be used to treat thyroid cancer. Iodine is also used as a catalyst in the industrial production of acetic acid and some polymers.

It is on the World Health Organization’s List of Essential Medicines.^[12]

In 1811, iodine was discovered by French chemist Bernard Courtois,^[13][14] who was born to a family of manufacturers of saltpetre (an essential component of gunpowder). At the time of the Napoleonic Wars, saltpetre was in great demand in France. Saltpetre produced from French nitre beds required sodium carbonate, which could be isolated from seaweed collected on the coasts of Normandy and Brittany. To isolate the sodium carbonate, seaweed was burned and the ashes washed with water. While investigating the cause of corrosion to the copper vessels used in the process,^[15] Courtois added an excess of sulfuric acid to the waste remaining and a cloud of violet vapour arose. He noted that the vapour crystallised on cold surfaces, forming dark crystals.^[16] Courtois suspected that this material was a new element but lacked funding to pursue it further.^[17]

Courtois gave samples to his friends, Charles Bernard Desormes (1777–1838) and Nicolas Clément (1779–1841), to continue research. He also gave some of the substance to chemist Joseph Louis Gay-Lussac (1778–1850), and to physicist André-Marie Ampère (1775–1836). On 29 November 1813, Desormes and Clément made Courtois’ discovery public by describing the substance to a meeting of the Imperial Institut de France.^[18] On 6 December 1813, Gay-Lussac found and announced that the new substance was either an element or a compound of oxygen and he found that it is an element.^[19][20][21] Gay-Lussac suggested the name “iode” (anglicised as “iodine”), from the Ancient Greek Ιώδης (iodēs, “violet”), because of the colour of iodine vapour.^[13][19] Ampère had given some of his sample to British chemist Humphry Davy (1778–1829), who experimented on the substance and noted its similarity to chlorine and also found it as an element.^[22] Davy sent a letter dated 10 December to the Royal Society stating that he had identified a new element called iodine.^[23] Arguments erupted between Davy and Gay-Lussac over who identified iodine first, but both scientists found that both of them identified iodine first and also knew that Courtois is the first one to isolate the element.^[17]

In 1873, the French medical researcher Casimir Davaine (1812–1882) discovered the antiseptic action of iodine.^[24] Antonio Grossich (1849–1926), an Istrian-born surgeon, was among the first to use sterilisation of the operative field. In 1908, he introduced tincture of iodine as a way to rapidly sterilise the human skin in the surgical field.^[25]

In early periodic tables, iodine was often given the symbol J, for Jod, its name in German; in German texts, J is still frequently used in place of I.^[26]

Iodine is the fourth halogen, being a member of group 17 in the periodic table, below fluorine, chlorine, and bromine; since astatine and tennessine are radioactive, iodine is the heaviest stable halogen. Iodine has an electron configuration of [Kr]5s²4d¹⁰5p⁵, with the seven electrons in the fifth and outermost shell being its valence electrons. Like the other halogens, it is one electron short of a full octet and is hence an oxidising agent, reacting with many elements in order to complete its outer shell, although in keeping with periodic trends, it is the weakest oxidising agent among the stable halogens: it has the lowest electronegativity among them, just 2.66 on the Pauling scale (compare fluorine, chlorine, and bromine at 3.98, 3.16, and 2.96 respectively; astatine continues the trend with an electronegativity of 2.2). Elemental iodine hence forms diatomic molecules with chemical formula I₂, where two iodine atoms share a pair of electrons in order to each achieve a stable octet for themselves; at high temperatures, these diatomic molecules reversibly dissociate a pair of iodine atoms. Similarly, the iodide anion, I⁻, is the strongest reducing agent among the stable halogens, being the most easily oxidised back to diatomic I₂.^[27] (Astatine goes further, being indeed unstable as At⁻ and readily oxidised to At⁰ or At⁺.)^[28]

The halogens darken in colour as the group is descended: fluorine is a very pale yellow, chlorine is greenish-yellow, bromine is reddish-brown, and iodine is violet.

Elemental iodine is slightly soluble in water, with one gram dissolving in 3450 mL at 20 °C and 1280 mL at 50 °C; potassium iodide may be added to increase solubility via formation of triiodide ions, among other polyiodides.^[29] Nonpolar solvents such as hexane and carbon tetrachloride provide a higher solubility.^[30] Polar solutions, such as aqueous solutions, are brown, reflecting the role of these solvents as Lewis bases; on the other hand, nonpolar solutions are violet, the colour of iodine vapour.^[29] Charge-transfer complexes form when iodine is dissolved in polar solvents, hence changing the colour. Iodine is violet when dissolved in carbon tetrachloride and saturated hydrocarbons but deep brown in alcohols and amines, solvents that form charge-transfer adducts.^[31]

The density, and the melting and boiling points of iodine follow the trend across all of the halogens of increasing with atomic number.^[32]: 405 Among the stable halogens, iodine has the largest electron cloud among them that is the most easily polarised, resulting in its molecules having the strongest Van der Waals interactions among the stable halogens. Similarly, iodine is the least volatile of the stable halogens, though the solid still can be observed to give off purple vapour.^[27] Due to this property iodine is commonly used to demonstrate sublimation directly from solid to gas, which gives rise to a misconception that it does not melt in atmospheric pressure.^[33] Because it has the largest atomic radius among the stable halogens, iodine has the lowest first ionisation energy, lowest electron affinity, lowest electronegativity and lowest reactivity of the stable halogens

• • Fisher Scientific: Offers a wide range of iodine products, including crystalline and analytical reagent grades.
  • Sigma-Aldrich (Merck): Provides high-purity iodine (e.g., 99.8% AR grade).
  • Carl ROTH: Stocks resublimated iodine (99.5%+) in various quantities.
  • TCI Chemicals: Supplies iodine as powder or lumps (>99.0% purity).
  • Spectrum Chemical: Offers, for example, analytical reagents. 

• • Appearance: Gray to black solid/crystal.
  • Purity: Commonly

    

    ≥99.5%is greater than or equal to 99.5 %

    ≥99.5%

    ,

    

    ≥99.8%is greater than or equal to 99.8 %

    ≥99.8%

    , or higher (Suprapur® 99.999% available).

  • Packaging: Ranges from 5g to 12kg or more.
  • Applications: Industrial, analytical, and laboratory use. 

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