Sodium iodide

Sodium iodide
Sodium iodide	Sodium iodide
Identifiers
CAS Number	7681-82-5 ; 13517-06-1 (dihydrate) ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:33167 ;
ChEMBL	ChEMBL1644695 ;
ChemSpider	5048 ;
ECHA InfoCard	100.028.800
PubChem CID	5238;
RTECS number	WB6475000;
UNII	F5WR8N145C ;
CompTox Dashboard (EPA)	DTXSID2041125 ;
	InChI InChI=1S/HI.Na/h1H;/q;+1/p-1 Key: FVAUCKIRQBBSSJ-UHFFFAOYSA-M ; InChI=1/HI.Na/h1H;/q;+1/p-1 Key: FVAUCKIRQBBSSJ-REWHXWOFAL;
	SMILES [Na+].[I-];
Properties
Chemical formula	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)
Solubility in water	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)
Acidity (pKa)	8–9.5
Refractive index (nD)	1.7745
Structure
Crystal structure	Halite
Coordination geometry	Octahedral
Thermochemistry
Std molar; entropy (S⦵298)	91 J·mol−1·K−1
Std enthalpy of; formation (ΔfH⦵298)	−288 kJ·mol−1
Hazards
	Occupational safety and health (OHS/OSH):
Main hazards	Irritant, can harm the unborn child
Flash point	Non-flammable
Safety data sheet (SDS)	[1]
Related compounds
Other anions	Sodium fluoride; Sodium chloride; Sodium bromide; Sodium astatide
Other cations	Lithium iodide; Potassium iodide; Rubidium iodide; Caesium iodide; Francium iodide
	Except where otherwise noted, data are 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

Monatomic NaI chains grown inside double-wall carbon nanotubes.^[4]

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:

{\ce {{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^[5] 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.^[6]

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) ^[7]

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 ^[8]

References

^ Seidell, Atherton (1919). Solubilities of inorganic and organic compounds c. 2. D. Van Nostrand Company. p. 655.
^ ^a ^b Zumdahl, Steven S. (2009). Chemical Principles 6th Ed. Houghton Mifflin Company. p. A23. ISBN 0-618-94690-X.
^ ^a ^b Lyday, Phyllis A. (2005) "Iodine and Iodine Compounds", pp. 382–390 in Ullmann's Encyclopedia of Industrial Chemistry, Vol. A14, Wiley-VCH, Weinheim, ISBN 978-3-527-30673-2 doi:10.1002/14356007.a14_381.
^ Senga, Ryosuke; Suenaga, Kazu (2015). "Single-atom electron energy loss spectroscopy of light elements". Nature Communications. 6: 7943. doi:10.1038/ncomms8943. PMC 4532884. PMID 26228378.
^ Sodium iodide. The Free Dictionary
^ Scintillation Materials. crystals.saint-gobain.com
^ Burgess, J. (1978). Metal Ions in Solution. New York: Ellis Horwood. ISBN 0-85312-027-7.
^ De Namor, Angela F. Danil; Traboulssi, Rafic; Salazar, Franz Fernández; De Acosta, Vilma Dianderas; De Vizcardo, Yboni Fernández; Portugal, Jaime Munoz (1989). "Transfer and partition free energies of 1 : 1 electrolytes in the water–dichloromethane solvent system at 298.15 K". Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases. 85 (9): 2705. doi:10.1039/F19898502705.

External links

[1] Seidell, Atherton (1919). Solubilities of inorganic and organic compounds c. 2. D. Van Nostrand Company. p. 655.

[b1-2] Zumdahl, Steven S. (2009). Chemical Principles 6th Ed. Houghton Mifflin Company. p. A23. ISBN 0-618-94690-X.

[Ullmann-3] Lyday, Phyllis A. (2005) "Iodine and Iodine Compounds", pp. 382–390 in Ullmann's Encyclopedia of Industrial Chemistry, Vol. A14, Wiley-VCH, Weinheim, ISBN 978-3-527-30673-2 doi:10.1002/14356007.a14_381.

[chains-4] Senga, Ryosuke; Suenaga, Kazu (2015). "Single-atom electron energy loss spectroscopy of light elements". Nature Communications. 6: 7943. doi:10.1038/ncomms8943. PMC 4532884. PMID 26228378.

[5] Sodium iodide. The Free Dictionary

[6] Scintillation Materials. crystals.saint-gobain.com

[7] Burgess, J. (1978). Metal Ions in Solution. New York: Ellis Horwood. ISBN 0-85312-027-7.

[8] De Namor, Angela F. Danil; Traboulssi, Rafic; Salazar, Franz Fernández; De Acosta, Vilma Dianderas; De Vizcardo, Yboni Fernández; Portugal, Jaime Munoz (1989). "Transfer and partition free energies of 1 : 1 electrolytes in the water–dichloromethane solvent system at 298.15 K". Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases. 85 (9): 2705. doi:10.1039/F19898502705.

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