Sodium iodide

Sodium iodide
Sodium iodide
CAS number 7681-82-5 YesY
13517-06-1 (dihydrate)
PubChem 5238
ChemSpider 5048 YesY
RTECS number WB6475000
Jmol-3D images Image 1
Molecular formula NaI
Molar mass 149.89 g/mol
Appearance white solid
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)
Solubility soluble in ethanol and acetone (39.9 g/100 mL)
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
 N (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Sodium iodide is a white, crystalline salt with chemical formula NaI used in radiation detection, treatment of iodine deficiency, and as a reactant in the Finkelstein reaction.



Sodium iodide is commonly used to treat and prevent iodine deficiency.

Sodium iodide is used in polymerase chain reactions, and also (as an acetone solution) in the Finkelstein reaction, for conversion of an alkyl chloride into an alkyl iodide. This relies on the insolubility of sodium chloride in acetone to drive the reaction.

R-Cl + NaI → R-I + NaCl

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 and has the highest light yield of the commonly used scintillators. 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.[1]

Solubility data

Solubility of NaI in various solvents
(g NaI / 100g of solvent at 25°C)
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


  1. ^ The Free Dictionary: sodium iodide 131I
  2. ^ Burgess, J. "Metal Ions in Solution" (Ellis Horwood, New York, 1978) ISBN 0-85312-027-7

See also

External links

Wikimedia Foundation. 2010.

Look at other dictionaries:

  • sodium iodide — n a crystalline salt NaI used as an iodine supplement and expectorant * * * [USP] a binary haloid, NaI, used in various conditions as a source of iodine. It is also used as an expectorant …   Medical dictionary

  • sodium iodide — noun a crystalline salt used like potassium iodide (Freq. 2) • Hypernyms: ↑iodide * * * noun : a crystalline salt NaI used like potassium iodide * * * Chem. a colorless or white, crystalline, deliquescent, water soluble solid, NaI, used chiefly… …   Useful english dictionary

  • sodium iodide — natrio jodidas statusas T sritis chemija formulė NaI atitikmenys: angl. sodium iodide rus. натрий иодистый; натрия иодид …   Chemijos terminų aiškinamasis žodynas

  • sodium iodide — Chem. a colorless or white, crystalline, deliquescent, water soluble solid, NaI, used chiefly in the manufacture of photographic emulsions, in organic synthesis, and as a disinfectant in veterinary medicine. * * * …   Universalium

  • sodium iodide — so′dium i′odide n. chem. a colorless or white, crystalline, deliquescent, water soluble solid, NaI, used in the manufacture of photographic emulsions, in organic synthesis, and as a disinfectant in veterinary medicine …   From formal English to slang

  • sodium iodide I 125 — sodium iodide labeled with 125I; administered orally or intravenously as a tracer in tests of thyroid functioning and in thyroid imaging …   Medical dictionary

  • Sodium-iodide symporter — The sodium iodide symporter (NIS) also known as solute carrier family 5, member 5 (SLC5A5) is an ion pump that actively transports iodide (I ) across the basolateral membrane into thyroid epithelial cells.cite journal | author = Dai G, Levy O,… …   Wikipedia

  • sodium iodide I 123 — [USP] sodium iodide labeled with 123I; administered orally or intravenously in thyroid uptake tests and thyroid imaging …   Medical dictionary

  • sodium iodide I 131 — [USP] sodium iodide labeled with 131I; used as a tracer in thyroid uptake tests and thyroid imaging and used in the treatment of hyperthyroidism and thyroid carcinoma; administered orally or intravenously …   Medical dictionary

  • Sodium fluoride — IUPAC name Sodium fluoride …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.