Iodine

IUPAC Name: Molecular iodine
Molecular Formula: I₂
Molecular Weight: 253.81 g/mol
Canonical SMILES: II
InChI: InChI=1S/I2/c1-2
EINECS: 231-442-4
Classification Code: Anti-Infective Agents; Anti-infective agents, local; Anti-infective, topical; Growth Substances; Human Data; Micronutrients; Reproductive Effect; Trace Elements
Melting Point: 113 °C(lit.)
storage temperature: Store at RT.
form: particles (round)
Water Solubility: 0.3 g/L (20 °C)
Index of Refraction: 1.788 
Molar Refractivity: 27.98 cm³ 
Molar Volume: 66.1 cm³
Surface Tension: 54.8 dyne/cm 
Density: 3.834 g/cm³ 
Enthalpy of Vaporization: 41.57 kJ/mol 
Boiling Point: 184.3 °C at 760 mmHg 
Vapour Pressure of Iodine (CAS NO.7553-56-2): 0.49 mmHg at 25 °C

 Iodine was discovered by Bernard Courtois in 1811. Charles Bernard Desormes (1777–1862) and Nicolas Clément (1779–1841), to continue research. He also gave some of the substance to Joseph Louis Gay-Lussac (1778–1850), a well-known chemist at that time, and to physicist André-Marie Ampère (1775–1836). On 29 November 1813, Dersormes and Clément made public Courtois’s discovery. 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). Davy did some experiments on the substance and noted its similarity to chlorine. Davy sent a letter dated December 10 to the Royal Society of London stating that he had identified a new element. element.

 Iodine (CAS NO.7553-56-2) is used for the manufacture of organic compounds, for the manufacture of potassium iodide and sodium iodide, and for the manufacture of other inorganic compounds. Iodine is used as a catalyst in the chlorination of organic compounds and in analytical chemistry for determination of the iodine numbers of oils. Iodine for medicinal, photographic, and pharmaceutical purposes is usually in the form of alkali iodides, prepared through the agency of ferrous iodide. It is also used for the manufacture of dyes and as a germicide. Simple iodine derivatives of hydrocarbons, such as iodoform (CHI₃), have an antiseptic action. Organic compounds containing iodine have been used as rubber emulsifiers, chemical antioxidants, and dyes and pigments.

 Iodine can be produced from iodates:
       IO₃^- + 3SO₂ + 3H₂O → I^- + 3SO₄^2- + 6H^-
            IO₃^- + I^- + 6H⁺ → 3I₂ + 3H₂O
 Iodine can also be produced from brine. This process consists of cleaning the solution (of clays and other materials), adding sulfuric acid to a pH <2.5 followed by treatment with gaseous chlorine:
               2I^- + Cl₂ → I₂ + 2Cl^-
after which the Iodine is recovered by a countercurrent air blow out step. process.

Reported in EPA TSCA Inventory.

When heated to decomposition it emits toxic fumes of I⁻ and various iodine compounds. Reacts vigorously with reducing materials.
Hazard Codes: Xn,N
Risk Statements: 36/37/38-50-20/21 
R36/37/38:Irritating to eyes, respiratory system and skin. 
R50:Very toxic to aquatic organisms. 
R20/21:Harmful by inhalation and in contact with skin.
Safety Statements: 26-61-25-23 
S26: In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. 
S61:Avoid release to the environment. Refer to special instructions / safety data sheets. 
S25:Avoid contact with eyes. 
S23:Do not breathe vapour.
RIDADR: UN 2056 3/PG 2
WGK Germany: 2
RTECS: NN1575000
HazardClass: 8
PackingGroup: III

OSHA PEL: CL 0.1 ppm
ACGIH TLV: CL 0.1 ppm
DFG MAK: 0.1 ppm (1.1 mg/m³)

For occupational chemical analysis use OSHA: #ID-177 or NIOSH: Iodine, 6005.

  Iodine (CAS NO.7553-56-2), its Synonyms are Actomar ; Diiodine ; Eranol ; Ethanolic solution of iodine ; Iodine Tincture USP ; Iodine colloidal ; Iodine crystals ; Iodine solution ; Iodine sublimed ; Iodine tincture ; Tincture iodine . It is violet-black crystals with a metallic luster and a sharp odor.