Sodium iodide
| Sodium iodide | |
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| Identifiers | |
| CAS number | 7681-82-5  , 13517-06-1 (dihydrate) |
| PubChem | 5238 |
| ChemSpider | 5048 |
| UNII | F5WR8N145C |
| ChEBI | CHEBI:33167 |
| ChEMBL | CHEMBL1644695  |
| RTECS number | WB6475000 |
| Jmol-3D images | Image 1 |
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| Properties | |
| Molecular formula | NaI |
| Molar mass | 149.89 g/mol |
| Appearance | white solid deliquescent |
| Odor | odorless |
| Density | 3.67 g/cm3 |
| Melting point |
661 °C, 934 K, 1222 °F |
| Boiling point |
1304 °C, 1577 K, 2379 °F |
| Solubility in water | 178.8 g/100 mL (20 °C) 184 g/100 mL (25 °C) 294 g/100 mL (70 °C) 302 g/100 mL (100 °C) |
| Solubility | soluble in ethanol and acetone (39.9 g/100 mL) |
| Acidity (pKa) | 8-9.5 |
| Refractive index (nD) | 1.7745 |
| Structure | |
| Coordination geometry |
Octahedral |
| Thermochemistry | |
| Std enthalpy of formation ΔfH |
−288 kJ·mol−1[1] |
| Standard molar entropy S |
91 J·mol−1·K−1[1] |
| Hazards | |
| MSDS | [1] |
| EU Index | Not listed |
| Main hazards | Irritant, can harm the unborn child |
| Flash point | Non-flammable |
| Related compounds | |
| Other anions | Sodium fluoride Sodium chloride Sodium bromide |
| Other cations | Lithium iodide Potassium iodide Rubidium iodide Caesium iodide |
 (verify) (what is:  / ?)Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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| Infobox references | |
Sodium iodide is a white, crystalline salt with the chemical formula NaI, and is used in radiation detection, treatment of iodine deficiency, and as a reactant in the Finkelstein reaction.
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Production[edit]
Sodium iodide is manufactured from the reaction between iodine and sodium hydroxide.
Uses[edit]
Food supplement[edit]
Sodium iodide, as well as potassium iodide, is commonly used to treat and prevent iodine deficiency. Iodized table salt contains one part sodium or potassium iodide to 100,000 parts of sodium chloride.[2]
Organic synthesis[edit]
Sodium iodide is used in the Finkelstein reaction, for conversion of an alkyl chloride into an alkyl iodide. This method relies on the insolubility of sodium chloride in acetone to drive the reaction:
- R-Cl + NaI → R-I + NaCl
Radiation physics and medicine[edit]
Sodium iodide activated with thallium, NaI(Tl), when subjected to ionizing radiation, emits photons (i.e., scintillate) and is used in scintillation detectors, traditionally in nuclear medicine, geophysics, nuclear physics, and environmental measurements. NaI(Tl) is the most widely used scintillation material. The crystals are usually coupled with a photomultiplier tube, in a hermetically sealed assembly, as sodium iodide is hygroscopic. Fine-tuning of some parameters (i.e., radiation hardness, afterglow, transparency) can be achieved by varying the conditions of the crystal growth. Crystals with a higher level of doping are used in X-ray detectors with high spectrometric quality. Sodium iodide can be used both as single crystals and as polycrystals for this purpose.
The radioactive iodide salt of sodium, Na131I, is used for the treatment of thyroid cancer and hyperthyroidism.[3]
Solubility data[edit]
| H2O | 184 |
| Liquid ammonia | 162 |
| Liquid sulfur dioxide | 15 |
| Methanol | 62.5 - 83.0 |
| Formic acid | 61.8 |
| Acetonitrile | 24.9 |
| Acetone | 28.0 |
| Formamide | 57 - 85 |
| Acetamide | 32.3 |
| Dimethylformamide | 3.7 - 6.4 |
| [4] | |
See also[edit]
References[edit]
- ^ a b Zumdahl, Steven S. (2009). Chemical Principles 6th Ed. Houghton Mifflin Company. p. A23. ISBN 0-618-94690-X.
- ^ Lyday, Phyllis A. "Iodine and Iodine Compounds" in Ullmann's Encyclopedia of Industrial Chemistry, 2005, Wiley-VCH, Weinheim, ISBN 978-3-527-30673-2 doi:10.1002/14356007.a14_381 Vol. A14 pp. 382–390.
- ^ The Free Dictionary: sodium iodide 131I
- ^ Burgess, J. "Metal Ions in Solution" (Ellis Horwood, New York, 1978) ISBN 0-85312-027-7
External links[edit]
- International Chemical Safety Card 1009 - Sodium Iodide (Anhydrous)
- Material Safety Data Sheet (MSDS) - Safety data for sodium iodide
- Sodium Iodide Consumer Information
