Sodium iodide
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| Identifiers | |||
|---|---|---|---|
7681-82-5  13517-06-1 (dihydrate)  | |||
| ChEBI | CHEBI:33167 | ||
| ChEMBL | ChEMBL1644695 | ||
| ChemSpider | 5048 | ||
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| Jmol-3D images | Image | ||
| PubChem | 5238 | ||
| RTECS number | WB6475000 | ||
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| UNII | F5WR8N145C | ||
| Properties | |||
| NaI | |||
| Molar mass | 149.89 g/mol | ||
| Appearance | white solid deliquescent | ||
| Odor | odorless | ||
| Density | 3.67 g/cm3 | ||
| Melting point | 661 °C (1,222 °F; 934 K) | ||
| Boiling point | 1,304 °C (2,379 °F; 1,577 K) | ||
| 158.7 g/100 mL (0 °C) 184.2 g/100 mL (25 °C) 227.8 g/100 mL (50 °C) 294 g/100 mL (70 °C) 302 g/100 mL (100 °C) [1] | |||
| Acidity (pKa) | 8-9.5 | ||
| Refractive index (nD) |
1.7745 | ||
| Structure | |||
| Octahedral | |||
| Thermochemistry | |||
| Std molar entropy (S |
91 J·mol−1·K−1[2] | ||
| Std enthalpy of formation (ΔfH |
−288 kJ·mol−1[2] | ||
| Hazards | |||
| MSDS | |||
| Main hazards | Irritant, can harm the unborn child | ||
| EU Index | Not listed | ||
| Flash point | Non-flammable | ||
| Related compounds | |||
| Other anions |
Sodium fluoride Sodium chloride Sodium bromide | ||
| Other cations |
Lithium iodide Potassium iodide Rubidium iodide Caesium iodide | ||
| Except where noted otherwise, data is given for materials in their standard state (at 25 °C (77 °F), 100 kPa) | |||
| verify (what is: /?) | |||
| Infobox references | |||
Sodium iodide (chemical formula NaI) is the salt of sodium and iodide. It is a white, crystalline solid that is used mainly as a nutritional supplement and in organic chemistry. It is produced industrially by acidic iodides and sodium hydroxide.[3]
Uses
Food supplement
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.[3]
Organic synthesis
Sodium iodide is used for conversion of an alkyl chlorides into an alkyl iodides. This method, the Finkelstein reaction, relies on the insolubility of sodium chloride in acetone to drive the reaction:
- R-Cl + NaI → R-I + NaCl
Nuclear medicine
Some radioactive iodide salts of sodium, including [125I]NaI and [131I]NaI, have radiopharmaceutical uses, such as in the treatment of thyroid cancer and hyperthyroidism[4] or as radiolabeling tracers in imaging (see Isotopes of iodine > Radioiodines I-123, I-124, I-125, and I-131 in medicine and biology).
Thallium-doped NaI(Tl) scintillators
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 wavelength of maximum emission is 415 nm.[5]
Solubility data
Sodium iodide exhibits high solubility in some organic solvents, unlike sodium chloride or even bromide. Its solubility of NaI in various solvents (g NaI/100 g of solvent at 25 °C) [6]
| H2O | 184.2 |
| Liquid ammonia | 162 |
| Liquid sulfur dioxide | 15 |
| Methanol | 62.5 - 83.0 |
| Formic acid | 61.8 |
| Acetonitrile | 24.9 |
| Acetone | 50.4425 |
| Formamide | 57 - 85 |
| Acetamide | 32.3 (41.5 °C) |
| Dimethylformamide | 3.7 - 6.4 |
| Dichloromethane | 0.009 [7] |
See also
References
- ↑ Seidell, Atherton (1919). Solubilities of inorganic and organic compounds c. 2. D. Van Nostrand Company. p. 655.
- ↑ 2.0 2.1 Zumdahl, Steven S. (2009). Chemical Principles 6th Ed. Houghton Mifflin Company. p. A23. ISBN 0-618-94690-X.
- ↑ 3.0 3.1 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
- ↑ Scintillation Materials
- ↑ Burgess, J. (1978). Metal Ions in Solution. New York: Ellis Horwood. ISBN 0-85312-027-7.
- ↑ Danil de Namor, A.F.; J. Chem. Soc., Faraday Trans. 1, 1989,85, 2705-2712 DOI: 10.1039/F19898502705
External links
- International Chemical Safety Card 1009 - Sodium Iodide (Anhydrous)
- Material Safety Data Sheet (MSDS) - Safety data for sodium iodide
- Sodium iodide as medication — Consumer Information
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