Chemical Fact Sheet
Iodine
| Chemical Abstract Number (CAS #) | 7553-56-2 |
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| Synonyms | ERANOL; IODE- (FRENCH); IODINE- ((127)I2); IODINE-COLLOIDAL; IODINE-CRYSTALS; IODINE-SUBLIMED; IODINE-127; IODIO-(ITALIAN); IOSAN-SUPERDIP; JOD- (GERMAN,POLISH); JOOD- (DUTCH); MOLECULAR-IODINE; Actomar; AI3-08544; Caswell-No-501; EPA-Pesticide-Chemical-Code-046905; (Componentof)-ioprep; Diiodine |
| Analytical Methods | SM4500I |
| Molecular Formula | I |
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Synopsis
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Iodine-(Gr. iodes, violet), I; at.wt. 126.90447(3); at.no. 53; m.p. 113.7 deg C; b.p. 184.4 deg C; density of the gas 11.27 g/l; sp.gr. solid 4.93 (20 deg C); valence 1, 3, 5, or 7. Discovered by Courtois in 1811. Iodine, a halogen, occurs sparingly in the form of iodides in sea water from which it is assimilated by seaweeds, in Chilean saltpeter and nitrate-bearing earth, known as caliche in brines from old sea deposits, and in brackish waters from oil and salt wells. Ultrapure iodine can be obtained from the reaction of potassium iodide with copper sulfate. Several other methods of isolating the element are known. Iodine is a bluish-black, lustrous solid, volatilizing at ordinary temperatures into a blue-violet gas with an irritating odor; it forms compounds with many elements, but is less active than the other halogens, which displace it from iodides. Iodine exhibits some metallic-like properties. It dissolves readily in chloroform, carbon tetrachloride, or carbon disulfide to form beautiful purple solutions. It is only slightly soluble in water. Iodine compounds are important in organic chemistry and very useful in medicine. Forty two isotopes and isomers are recognized. Only one stable isotope, 127I is found in nature. The artificial radioisotope 131I, with a half-life of 8 days, has been used in treating the thyroid gland. The most common compounds are the iodides of sodium and potassium (KI) and the iodates (KIO3). Lack of iodine is the cause of goiter. Iodides, and thyroxin which contains iodine, are used internally in medicine, and a solution of KI and iodine in alcohol is used for external wounds. Potassium iodide finds use in photography. The deep blue color with starch solution is characteristic of the free element. Care should be taken in handling and using iodine as contact with the skin can cause lesions; iodine vapor is intensely irritating to the eyes and mucous membranes. Elemental iodine costs about 25 to 75 cents/g dependency on purity and quantity. |
| Use | CATALYST IN ALKYLATION & CONDENSATION OF AROMATIC AMINES; IN SULFONATION & SULFATIONS; MANUFACTURE OF GERMICIDES, ANTISEPTICS; IMPORTANT REAGENT IN ANALYTICAL CHEMISTRY; ARTIFICIAL ISOTOPES OF IODINE ARE USED IN BIOLOGICAL, BIOCHEMICAL & CHEMICAL STRUCTURE RESEARCH; REDUCES FRICTION OF HARD SURFACES, INCL STAINLESS STEEL & GLASS. MEDICATION (VET): INTERNALLY FOR GOITER, HYPOTHYROIDISM, IN IODINE DEFICIENCY; TOPICALLY AS ANTISEPTIC, DISINFECTANT; COUNTERIRRITANT & TO PROMOTE ABSORPTION. MEDICATION: ANTIHYPERTHYROID; TOPICAL ANTI-INFECTIVE. TO RENDER CONTAMINATED WATER SAFE FOR DRINKING. BACTERICIDE, FUNGICIDE, AMEBICIDE. CHEM INTERMED FOR INORGANIC IODIDES, POTASSIUM IODIDE, & ORGANIC IODINE CMPD. DYES (ANILINE DYES, PHTHALEIN DYES); SPECIAL SOAPS. A DISINFECTANT OF INANIMATE OBJECTS, BUT BOTH ITS LIMITED ABILITY TO KILL SPORES & ITS ABILITY TO ATTACK METALS & OTHER MATERIALS MUST BE KEPT IN MIND. MEDICATION: IN TREATMENT OF DENDRITIC KERATITIS. THE CORNEAS OF PATIENTS HAVE BEEN EXPOSED TO AIR PRACTICALLY SATURATED WITH IODINE VAPOR STAINING OF CORNEAL EPITHELIUM & LOSS OF THIS LAYER, BUT COMPLETE RECOVERY IN TWO OR THREE DAYS. TINCTURE OF IODINE, SWABBED ON CORNEA, HAS BEEN EMPLOYED WITH SAME RESULTS. MEDICATION: THE ARTIFICIAL RADIOISOTOPE (131)I, WITH A HALF-LIFE OF 8 DAYS, HAS BEEN USED IN TREATING THE THYROID GLAND. LACK OF IODINE IS THE CAUSE OF GOITER. THE IODIDE, & THYROXINE WHICH CONTAIN IODINE, ARE USED INTERNALLY. MEDICATION: A 2% SOLUTION OF IODINE IN GLYCERIN IS THE IODINE PREPARATION OF CHOICE FOR MUCOUS MEMBRANES. MEDICATION: CHIEF USE OF SOLN OF ELEMENTAL IODINE IS IN THE DISINFECTION OF THE SKIN MAY ALSO BE EMPLOYED IN THE TREATMENT OF WOUNDS & ABRASIONS. APPLIED TO ABRADED TISSUE, AQ SOLN ARE LESS IRRITATING THAN THE TINCTURE IN TREATMENT OF CUTANEOUS INFECTIONS DUE TO BACTERIA & FUNGI, USP TINCTURE OR SOLN MAY BE EMPLOYED. MEDICATION: PATIENTS WITH HYPERTHYROIDISM & PREGNANCY TREATED WITH DESICCATED THYROID (60-120 MG DAILY) & STRONG IODINE SOLN (1 MINIM DAILY) FROM DAY OF SUBTOTAL THYROIDECTOMY UNTIL THE TERMINATION OF PREGNANCY; ONLY 1 FETAL LOSS (4.7%) OCCURRED. IODINE HAS BEEN USED TO DISINFECT BOTH DRINKING WATER SUPPLIES & SWIMMING POOLS WITH EXCELLENT RESULTS. MEDICATION: TO TREAT THYROTOXIC CRISIS OR NEONATAL THYROTOXICOSIS. |
| Consumption Patterns | 42.7% AS AN INTERMED FOR POTASSIUM IODIDE; 31.7% AS AN INTERMED FOR INORG IODINE CMPD; AND 25.7% AS AN INTERMED FOR ORG IODINE CMPD (1964). DERIVATIVE: CATALYSTS, 22%; PHARMACEUTICAL, 20%; ANIMAL FEED SUPPLEMENTS, 18%; SANITARY OR INDUSTRIAL DISINFECTANTS, 12%; STABILIZERS, 11%; INKS & COLORANTS, 6%; PHOTOGRAPHIC, 5%; MISC, 6% (1984) |
| Apparent Color | BLUISH-BLACK SCALES OR PLATES; DIATOMIC; RHOMBIC, VIOLET-BLACK CRYSTALS WITH METALLIC LUSTER |
| Boiling Point | 184.35 deg C @ 1 atm |
| Melting Point | 113.50 DEG C |
| Molecular Weight | 253.81 |
| Density | 4.93 (SOLID @ 25 DEG C) |
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Odor Threshold Concentration |
Odor low= 9.00 mg/cu m; Odor high= 9.00 mg/cu m; Irritating Concn= 2.0 mg/cu m |
| Sensitivity Data | Irritation of nose skin rash. IODINE VAPOR IS IRRITATING TO THE EYE. MAN CAN WORK UNDISTURBED AT CONCN 0.1 PPM WORK IS POSSIBLE BUT DIFFICULT AT 0.15 TO 0.2 PPM. WORK IS IMPOSSIBLE AT 0.3 PPM. A CONCENTRATION OF 0.57 PPM WAS TOLERATED FOR 5 MIN WITHOUT EYE IRRITATION, WHICH WAS EXPERIENCED IN 2 MIN AT 1.63 PPM. |
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Chemical and Physical Properties |
ONLY ONE STABLE ISOTOPE, (127)IODINE, IS FOUND IN NATURE; DENSITY: 11.27 G/L (GAS) HEAT CAPACITY (CONSTANT PRESSURE): 13.011 CAL/MOLE/DEG C NATURAL ISOTOPE: 127 (100%); ISOTOPES RANGE IN MASS NUMBER FROM 117 TO 139; RADIOACTIVE TRACER ELEMENTS: 124, 125, 128, 131, 132 DISSOLVES IN IODIDE SOLUTIONS TO FORM TRIIODIDES SUCH AS SODIUM TRIIODIDE & POTASSIUM TRIIODIDE. SOLVENTS CONTAINING NITROGEN ATOMS, SUCH AS PYRIDINE, QUINOLINE, OR AMINES, DISSOLVE IODINE TO FORM BROWN SOLUTIONS CHLOROFORM, CARBON TETRACHLORIDE, CARBON DISULFIDE, & ESPECIALLY PHOSPHORUS TRICHLORIDE GIVE VIOLET SOLUTIONS; VAPOR IS VIOLET IN SOLUTION WITH FLUORINATED AMINES, A VIOLET COLOR IS GIVEN; SOL IN WATER IS INCREASED BY ALKALI BROMIDES & DECREASED BY SULFATES & NITRATES Heat of fusion: 2270 cal/g mole Density @ 101.3 kPa: 3.96 @ 120 deg C (liquid) IODINE IS A POWERFUL OXIDIZING AGENT |
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Environmental Fate |
ABUNDANCE IN IGNEOUS ROCKS:3X10-5% BY WT; IN SEAWATER 5X10-8% BY WT. SEVERAL NATURAL SOURCES INCLUDE: SEAWATER (1,000 TONS OF IODINE IN 1 CUBIC MILE), SEAWEED, SALT BRINES, AND CHILEAN SALTPETER (ONCE THE PRIMARY SOURCE). A DYNAMIC LINEAR COMPARTMENT MODEL OF THE GLOBAL IODINE CYCLE WAS DEVELOPED TO ESTIMATE RADIOLOGICAL IMPACTS ON THE WORLD POPULATION FROM RELEASES OF (129)IODINE TO THE ENVIRONMENT. THE GLOBAL RADIOLOGICAL IMPACTS ON MAN FROM A GIVEN RELEASE OF (129)IODINE WERE ESTIMATED. |
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Disposal |
At the time of review, criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices. IODINE MAY BE DISPOSED OF IN SEALED CONTAINERS. React with large volumes of reducing agent (hypo- or bisulfites or ferrous salts) solution, neutralize. Alternatively, iodine may be recovered from various process waste streams. |
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