Courses
Courses for Kids
Free study material
Offline Centres
More
Store Icon
Store

Sodium Iodide NaI Properties Preparation and Applications

Reviewed by:
ffImage
hightlight icon
highlight icon
highlight icon
share icon
copy icon

What Is Sodium Iodide Definition Formula Structure Reactions and Uses

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 

Property

Molecular Weight 

149.8942 g/mol

Hydrogen Bound Donar Count

0

Hydrogen Bond Acceptor Count

1

Rotatable Bond Count

0

Exact Mass

149.89424 g/mol

Monoisotopic Mass

149.89424 g/mol

Topological Polar Surface Area

0 A2

Heavy Atom Count 

2


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:-

Image will be uploaded soon

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.

FAQs on Sodium Iodide NaI Properties Preparation and Applications

1. What is sodium iodide?

Sodium iodide is an ionic compound with the chemical formula NaI, composed of sodium cations (Na+) and iodide anions (I-).

  • It is a white, crystalline solid at room temperature.
  • It forms when sodium metal reacts with iodine.
  • It is highly soluble in water due to strong ion–dipole interactions.
Sodium iodide is commonly studied in inorganic chemistry and used in medicine and laboratory reactions.

2. What is the formula for sodium iodide?

The chemical formula for sodium iodide is NaI.

  • Sodium forms a +1 ion (Na+).
  • Iodine forms a -1 ion (I-).
  • The charges balance in a 1:1 ratio, giving NaI.
This simple ionic formula reflects electrical neutrality in the compound.

3. How is sodium iodide formed?

Sodium iodide is formed by the direct combination of sodium metal and iodine gas in a synthesis reaction.

  • Balanced equation:
2Na(s) + I2(s) → 2NaI(s)
  • Sodium is oxidized to Na+.
  • Iodine is reduced to I-.
This is a redox reaction commonly demonstrated in basic inorganic chemistry.

4. Is sodium iodide soluble in water?

Yes, sodium iodide is highly soluble in water because it is an ionic compound with strong hydration of Na+ and I- ions.

  • In water, it dissociates completely:
NaI(s) → Na+(aq) + I-(aq)
  • The solution conducts electricity due to free-moving ions.
  • It behaves as a strong electrolyte.

5. What type of bond is present in sodium iodide?

Sodium iodide contains an ionic bond formed by the electrostatic attraction between Na+ and I- ions.

  • Sodium loses one electron to form Na+.
  • Iodine gains one electron to form I-.
  • The oppositely charged ions form a crystal lattice.
This bonding explains its high melting point and solubility in water.

6. What is the molar mass of sodium iodide?

The molar mass of sodium iodide (NaI) is approximately 149.89 g/mol.

  • Atomic mass of Na ≈ 22.99 g/mol
  • Atomic mass of I ≈ 126.90 g/mol
  • Total = 22.99 + 126.90 = 149.89 g/mol
This value is used in stoichiometric calculations and molarity problems.

7. What are the uses of sodium iodide?

Sodium iodide is used in medicine, organic synthesis, and analytical chemistry.

  • In medicine, it helps treat iodine deficiency and thyroid disorders.
  • In organic chemistry, it is used in the Finkelstein reaction to substitute halides.
  • It is used in radiation detection when combined with thallium in NaI(Tl) detectors.
Its high solubility and iodide ion reactivity make it chemically useful.

8. What happens when sodium iodide reacts with chlorine?

When sodium iodide reacts with chlorine, chlorine displaces iodine in a halogen displacement reaction.

  • Balanced equation:
2NaI(aq) + Cl2(g) → 2NaCl(aq) + I2(s)
  • Chlorine is more reactive than iodine.
  • Iodide ions are oxidized to iodine.
This reaction demonstrates halogen reactivity trends in Group 17.

9. Is sodium iodide an acid, base, or salt?

Sodium iodide is a neutral salt formed from a strong base (NaOH) and a strong acid (HI).

  • NaOH + HI → NaI + H2O
  • Both parent compounds are strong electrolytes.
  • The resulting aqueous solution is approximately neutral (pH ≈ 7).
Therefore, NaI does not significantly hydrolyze in water.

10. What is the difference between sodium iodide and potassium iodide?

The main difference between sodium iodide (NaI) and potassium iodide (KI) is the cation present—Na+ versus K+.

  • Both are ionic iodide salts.
  • Both are highly soluble in water.
  • They have different molar masses (NaI ≈ 149.89 g/mol; KI ≈ 166.00 g/mol).
Chemically, they behave similarly, but their physical properties and medical dosing differ due to the metal ion.