Sodium Iodide

What is Sodium Iodide?

Sodium iodide is a salt that is formed by the ionic reaction of sodium metal and iodine. The sodium iodide formula is NaI. Under standard conditions, it is a white, soluble solid which includes a 1:1 blend of sodium cations (Na+) and iodide anions (I−) in a lattice grid. Its main uses are in the field of medicine as a nutritional supplement and as additives. It is created when the salt is produced when acidic iodides respond with sodium hydroxide. It is a chaotropic salt. Sodium iodide is a metal iodide salt with a Na(+) counterion. It is an inorganic sodium salt and an iodide salt. 

Sodium iodide has many interesting chemical and physical properties. It is created by the combination of an acid and a base yielding no by‐products.

The physical properties of sodium iodide are mentioned below.

  • The melting point of sodium iodide is 661 degrees C. 

  • The boiling point of sodium iodide is 1304 degrees Celsius.

  • It is a strong deliquescent, which absorbs moisture and transforms into a solution. 

  • It is a white and odourless crystal or powder

Properties of Sodium Lodide

Property Value Name 


Molecular Weight 

149.8942 g/mol

Hydrogen Bound Donar Count


Hydrogen Bond Acceptor Count


Rotatable Bond Count


Exact Mass

149.89424 g/mol

Monoisotopic Mass

149.89424 g/mol

Topological Polar Surface Area

0 A2

Heavy Atom Count 


Chemical Properties Of Sodium Iodide

Sodium iodide is extremely soluble in water and has an ionic crystal lattice structure.

Sodium iodide structure is given below:-

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Sodium iodide is not only dissolvable in water but also some other natural solvents. It is affected by air, moisture, and light, and strong NaI solid turns brownish colored on introduction to air or light, because of the development of iodine gas. It additionally responds explosively with various oxidants, solid acids, and bromine trihalides, creating iodine.

Iodides (counting sodium iodide) are oxidized by oxygen strongly (O2) to iodine gas(I2).

The resultant I2 and I-complex which is formed as a byproduct end up shaping the triiodide complex, which is rather yellow in color, in contrast to the white shade of sodium iodide. 

Water quickens the oxidation procedure, and iodide can likewise create I2 gas by simple photooxidation. This is one of the biggest reasons sodium iodide ought to be put away under dim lights, low temperature, and low moisture conditions. It is better to maintain precautions and keep the solid away from external elements. 

NaI + Cl2 -----> NaCl + I2

NaI + 4H2O ------> [Na(H2O)4]+  + I-

Hot sodium will likewise react along with halogen elements such as bromine or iodine gas fumes to create sodium bromide or sodium iodide. Every one of the usual reactions which result in the formation of sodium iodide gives out an orange fire and a white solid ionic lattice structure. 

Iodide has a negative charge which implies it holds additional electrons which act as its valency. When it can obtain other iodine atoms it can lose the electrons to form stable I2 gas. The lost electrons will be picked up by another dependent atom or molecule which will be reduced into making iodide a good reducing agent. 

Uses of Sodium Lodide

  • Sodium iodide is regularly utilized as a dietary iodine supplement and used to prepare pure NaCl as for table salt (NaCl).  It is used to treat and prevent iodine deficiency. This disease can adversely affect the endocrine system. But NaI can help alleviate the symptoms by providing a source of iodine. 

  • Another regular usage of (Sodium iodide formula) NaI is in atomic medication, as radioactive sodium iodide, (for example, NaI125 and NaI131) . Its similar subordinates are significant radiopharmaceuticals that are utilized for stopping and preventing thyroid malignant growth and hyperthyroidism, and furthermore as imaging tracers. 

  • Sodium iodide is additionally utilized as a reagent in chemical combinations to get the resultant different alkyl iodides for other uses.

  • This halide salt is utilized in medication as a tracer and detector  for such medical gadgets as computer‐assisted tomography outputs and PET scans.

FAQ (Frequently Asked Questions)

1. Explain the oxidation of Sodium Iodide by sulphuric acid and its general properties?

Concentrated sulphuric acid is not strong enough as a sufficient oxidizing agent to oxidize fluoride or chloride particles. In those cases, all you get is the hot gas of the hydrogen halide - hydrogen fluoride or hydrogen chloride. Iodide particles are more grounded in reducing agents than bromide particles are. They are oxidized to iodine by the concentrated sulphuric acid. It is utilized primarily as a nourishing enhancement. In turn, the sulphuric acid gets reduced. The iodide particles have the only property to reduce sulphuric acid. Sodium iodide is delivered by the response between sodium hydroxide and iodine or hydroiodic acid. The NaI compound can also be obtained by adding sodium carbonate with any hydroiodic acid.

2. How to differentiate sodium chloride(a salt)  or sodium fluoride from sodium iodide( slightly poisonous)?

The Silver nitrate test is utilized for detecting the different halides attached to the same cation in the salts. The halogens can be identified on the basis of the resultant reaction with the silver nitrate   On account of a fluoride salt when silver nitrate is included no visible is formed because of the development of dissolvable silver fluoride. While on account of iodides, a steady silver iodide solution is shaped as a product of the above reaction. It is pale yellow in color. Whereas when it comes to the chloride salts, silver chloride precipitate is formed out of the reaction which is bright white in color. 

Sodium chloride and Sodium iodide can be thus recognized with the assistance of Silver nitrate test 

1) NaCl 

NaCl+ AgNO3------> NaNO3 + AgCl

2) NaI

NaI + AgNO3 ------->NaNO3 + AgI