Main Difference – Sodium Chloride vs Sodium Iodide
Sodium is a chemical element having the atomic number 11 and chemical symbol “Na.” This symbol comes from the Latin word “Natrium” for sodium carbonate. Sodium forms a number of compounds that are very useful in laboratories as well as in industries. The salts of sodium are alkaline. Sodium chloride and sodium iodide are two sodium halide compounds. Halides are anions formed by the group 7 elements. The main difference between sodium chloride and sodium iodide is that sodium chloride is composed of a chloride ion bonded to a sodium ion whereas sodium iodide is composed of an iodide ion bonded to a sodium ion.
Key Areas Covered
1. What is Sodium Chloride
– Definition, Structure, Properties
2. What is Sodium Iodide
– Definition, Structure, Properties
3. What are the Similarities Between Sodium Chloride and Sodium Iodide
– Outline of Common Features
4. What is the Difference Between Sodium Chloride and Sodium Iodide
– Comparison of Key Differences
Key Terms: Anion, Cation, Halide, Sodium, Sodium Chloride, Sodium Halide, Sodium Iodide
What is Sodium Chloride
Sodium chloride is an inorganic compound composed of sodium cation and chloride anion. It is commonly known as salt since the salt we consume as a food additive is mainly composed of sodium chloride along with some trace compounds (sodium chloride about 99.8% in salt). The chemical formula of sodium chloride is NaCl.
Sodium chloride is an ionic compound. It has 1:1 sodium ions and chloride ions. Sodium chloride is the compound that is responsible for the characteristic taste in sea water. The formula weight of sodium chloride is 58.44 g/mol. Sodium chloride is white when it is pure. It appears as transparent or translucent cubic crystals. The melting point of sodium chloride is 801oC, and the boiling point is 1465oC. It is well soluble in water. In the crystal structure of sodium chloride, each ion is surrounded by six ions of opposite charge. These ions are located in a regular octahedron structure.
Figure 1: Crystal Structure of Sodium Chloride
Sodium chloride is hygroscopic. This means it can absorb water vapor from the air when exposed to the atmosphere. This compound is essential for us to maintain the electrolytic balance in our body. It is also used to preserve some food items.
What is Sodium Iodide
Sodium iodide is an inorganic chemical compound composed of sodium ions and iodide ions. The chemical formula of this compound is NaI. It is an ionic compound. It has a white color and is a water-soluble compound.
The formula mass of sodium iodide is 149.89 g/mol. The compound contains sodium cations and iodide anions. Therefore, it is a sodium halide compound. This compound can be produced industrially by the reaction between sodium hydroxide and hydroiodic acid.
NaOH + HI → NaI + H2O
The melting point of sodium iodide is 651 °C, and boiling point is 1304 °C. Sodium iodide is a deliquescent solid compound. This means it can absorb water vapor from the atmosphere and turn into a solution. Solid compound gets a brown color when exposed to air or light, due to the formation of iodine fumes.
Figure 2: Crystal Structure of Sodium Iodide
Sodium iodide is used as a supplement of iodine. It is mixed with sodium chloride when producing salt. Therefore, what we consume as salt is an iodine supplement that helps to avoid iodine deficiency.
Similarities Between Sodium Chloride and Sodium Iodide
- Both compounds are sodium halides.
- Both can absorb water vapor.
- Both are composed of sodium cations.
- Both are white
- Both have a crystal structure.
Difference Between Sodium Chloride and Sodium Iodide
Definition
Sodium Chloride: Sodium chloride is an inorganic compound composed of sodium cation and chloride anion.
Sodium Iodide: Sodium iodide is an inorganic chemical compound composed of sodium ions and iodide ions.
Chemical Formula
Sodium Chloride: The chemical formula of Sodium chloride is NaCl.
Sodium Iodide: The chemical formula of Sodium iodide is NaI.
Formula Mass
Sodium Chloride: The formula mass of Sodium chloride is 58.44 g/mol.
Sodium Iodide: The formula mass of Sodium iodide is 149.89 g/mol.
Melting Point and Boiling Point
Sodium Chloride: The melting point of sodium chloride is 801°C, and the boiling point is 1465°C.
Sodium Iodide: The melting point of sodium iodide is 651°C, and boiling point is 1304°C.
Nature of Compound
Sodium Chloride: Sodium chloride is hygroscopic.
Sodium Iodide: Sodium iodide is deliquescent.
Conclusion
Sodium can form many different compounds. Sodium chloride and sodium iodide are such two compounds that are sodium halides. The main difference between sodium chloride and sodium iodide is that sodium chloride is composed of a chloride ion bonded to a sodium ion whereas sodium iodide is composed of an iodide ion bonded to a sodium ion.
References:
1. Wood, Frank Osborne, et al. “Salt (NaCl).” Encyclopædia Britannica, Encyclopædia Britannica, inc., 4 May 2017, Available here.
2. “Sodium Chloride | NaCl | Uses, Benefits, and Safety Facts.” ChemicalSafetyFacts.org, 22 Sept. 2017, Available here.
3. “Sodium iodide.” Wikipedia, Wikimedia Foundation, 2 Dec. 2017, Available here.
Image Courtesy:
1. “Sodium chloride crystal” By Walkerma – Own work by the original uploader (Public Domain) via Commons Wikimedia
2. “Sodium-iodide-3D-ionic” By Benjah-bmm27 – Own work (Public Domain) via Commons Wikimedia
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