Difference Between Iodine and Resublimed Iodine

Key Difference – Iodine vs Resublimed Iodine
 

Iodine is a chemical element having the atomic number 53 and chemical symbol I. This chemical element belongs to the group of halogens in the periodic table. Iodine is known for its special ability to undergo sublimation. Sublimation is the vaporization of iodine crystals without going through a liquid phase. But if the sublimation and deposition are done repeatedly, we can get a pure form of iodine known as resublimed iodine. The key difference between iodine and resublimed iodine is that iodine is a chemical element having symbol I whereas resublimed iodine is a compound having chemical formula I₂.

CONTENTS

1. Overview and Key Difference
2. What is Iodine 
3. What is Resublimed Iodine
4. Side by Side Comparison –  Iodine vs Resublimed Iodine in Tabular Form
5. Summary

What is Iodine?

Iodine is a chemical element having the atomic number 53 and chemical symbol I. It is a member of the halogen group. Halogen group is the group 17 of the periodic table. Iodine is the largest halogen since it has the highest atomic number among other halogens in that group. Iodine is a nonmetal.

The melting point of iodine is 113.7°C. Therefore iodine exists as a solid at room temperature and pressure. The boiling point of iodine is 184.3°C. Iodine crystals can also undergo sublimation.

The most stable oxidation state of iodine is -1. This is because, when one electron is added to an iodine atom, all the orbitals of iodine are filled with electrons, which is a very stable state. The electrons configuration of iodine is [Kr] 4d¹⁰ 5s² 5p⁵. The added electron fill the outermost 5p orbital. This forms the iodide anion (I^–). Therefore iodine is a good oxidizing agent (a substance that can undergo reduction by oxidizing a different compound). However, the atomic radius of iodine is higher than halogen atoms; hence iodine has a low charge density. This makes it less reactive than other halogens. This makes iodine the least reactive oxidizing agent (among halogens).

Solid iodine appears as dark violet crystals. Liquid iodine and iodine vapor have brilliant violet color. Iodine crystals are highly soluble in nonpolar solvents. Ex: hexane. When dissolved in hexane, it forms a brown colored liquid solution.

What is Resublimed Iodine?

Resublimed iodine is iodine that is sublimed for a second or further time. Sublimation of iodine is the conversion of solid iodine into iodine vapor directly, without going through a liquid phase. This term should not be confused with “de-sublimation”, which is the reverse process of sublimation. The process includes the sublimation of iodine, then deposition as crystals, followed by sublimation again.

Resublimed iodine is purer than normal iodine; the purity is about 99-100%. The chemical formula of resublimed iodine is I₂.

What is the Difference Between Iodine and Resublimed Iodine?

Summary – Iodine vs Resublimed Iodine

Iodine is a halogen, commonly used as an oxidizing agent. Resublimed iodine is produced from iodine crystals to get a pure form of molecular iodine. The key difference between iodine and resublimed iodine is that iodine is a chemical element having symbol I whereas resublimed iodine is a compound having chemical formula I₂.

Reference:

1. “Iodine (Resublimed Crystals/USP), Fisher Chemical, Available here.
2. “What is resublimation?” Answers, Yahoo!, Available here.
3. “Iodine.” Wikipedia, Wikimedia Foundation, 21 Feb. 2018, Available here.

Image Courtesy:

1. “Sample of iodine” By LHcheM – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “Iodine-evaporating” By Jurii –  (CC BY 3.0) via Commons Wikimedia