Iodine | Descriptions, Properties, Uses & Facts

Iodine | Descriptions, Properties, Uses & Facts

Iodine: A Comprehensive Exploration of Iodine and Its Applications


In the vast realm of chemistry, certain elements captivate our attention with their unique properties and diverse applications. Iodine, a non-metal halogen, is one such element that plays a crucial role in various aspects of our lives. From its chemical properties to its practical applications in medicine and everyday products, iodine has secured its place as an indispensable element. In this blog, we will delve into the fascinating world of iodine, exploring its symbol, atomic number, atomic mass, electron configuration, valency, chemical and physical properties, compounds, reactions with other elements, occurrence, production, and its significance in various iodine-containing compounds.

Iodine Basics:

Symbol: I

Atomic Number: 53

Atomic Mass: 126.9045 u

Electron Configuration: [Kr] 4d¹⁰ 5s² 5p⁵ or

Electron Configuration long form: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁵

Valency: -1, +1, +3, +5, +7

Chemical and Physical Properties:

Iodine, in its elemental form, is a shiny purple-black solid with a distinct odor. It has a melting point of 113.7 degrees Celsius and a boiling point of 184.3 degrees Celsius. Known for its sublimation ability—changing from a solid directly into a gas—Iodine showcases a vibrant violet color when in a gaseous state, adding to its visual appeal.

Iodine Compounds:

Iodine readily forms compounds with various elements and molecules. Common iodine compounds include hydrogen iodide (HI), iodine pentoxide (I2O5), and iodine trichloride (ICl3). These compounds exhibit diverse properties and applications, contributing to fields such as medicine, industry, and research.

Chemical Reactions with Other Elements:

Iodine engages in chemical reactions with different elements, showcasing its versatile nature. It reacts with metals like sodium and potassium, forming iodide salts. The reactions with non-metals, such as hydrogen and oxygen, yield hydrogen iodide and iodine pentoxide, respectively.

Occurrence and Production:

Iodine is often found in trace amounts in certain minerals and seawater. However, the primary source of iodine extraction is from deposits of sodium iodate and sodium periodate. The production process involves reducing these compounds to release elemental iodine, which is then purified for various applications.

Iodine in Common Products:

1. Potassium Iodide (KI):

  • Used in medical applications and as a supplement to prevent iodine deficiency.
  • Plays a crucial role in nuclear emergencies to protect the thyroid from radioactive iodine exposure.

2. Lugol's Iodine Solution:

  • A combination of iodine and potassium iodide in water, Lugol's solution is widely used in laboratories for various tests.
  • Applied topically for its antiseptic properties.

3. Povidone Iodine:

  • A popular antiseptic used in medicine and surgery.
  • Known for its broad-spectrum antimicrobial activity.

4. Iodized Salt:

  • A common household item fortified with iodine to prevent iodine deficiency disorders.

5. Liquid Iodine:

  • Used as a dietary supplement to maintain optimal thyroid function.

Iodine is a versatile element with a range of uses and interesting facts. Let's explore some of its practical applications and intriguing aspects:

Uses of Iodine:

1. Medical Applications:

Antiseptic: Iodine and iodine-containing compounds like povidone iodine are widely used as antiseptics to disinfect wounds and surgical instruments.

Thyroid Health: Iodine is essential for the production of thyroid hormones and proper functioning of thyroid. Iodine deficiency can lead to thyroid-related disorders, making iodine supplementation crucial for maintaining thyroid health.

Radiation Protection: Potassium iodide is used to protect the thyroid gland from radioactive iodine exposure in the event of a nuclear accident.

2. Dietary Supplementation:

Iodine is added to salt in the form of iodized salt to prevent iodine deficiency disorders. This is a common method of ensuring an adequate intake of iodine in the diet.

3. Laboratory and Analytical Chemistry:

Lugol's solution, a mixture of iodine and potassium iodide, is used as a staining reagent in laboratory tests and as a visualization tool in microscopy.

Iodine is employed in titration reactions and chemical analyses due to its ability to react with certain compounds and form characteristic color changes.

4. Water Purification:

Iodine is used in the purification of water as it effectively kills bacteria, viruses, and other microorganisms. Iodine tablets or solutions are often used by hikers and campers to disinfect water from natural sources.

5. Photography:

In the past, iodine was used in the production of daguerreotypes, an early form of photography. It played a role in sensitizing photographic plates.

6. Industrial Applications:

Iodine is used in the production of certain polymers and dyes.

It serves as a catalyst in some chemical reactions.

Facts about Iodine:

1. Unique Physical State:

Iodine undergoes sublimation, transitioning directly from a solid to a gas without passing through the liquid phase. This property is often demonstrated by the distinctive violet vapor it produces.

2. Abundance in Seawater:

Although iodine is not abundant in the Earth's crust, it is found in relatively higher concentrations in seawater. Extraction from underwater sources is one method of obtaining iodine.

3. Health Impacts:

Iodine deficiency can lead to serious health issues, including goiter, hypothyroidism, and intellectual disabilities in severe cases, especially during pregnancy.

4. Radioactive Iodine:

Iodine-131, a radioactive isotope of iodine, is used in medical treatments for hyperthyroidism and thyroid cancer. However, it can also be released during nuclear accidents and poses health risks due to its radioactivity.

5. Chemical Reactivity:

Iodine reacts with starch, producing a distinctive blue-black color. This reaction is often used as a test for the presence of starch in chemical and biological analyses.

6. Halogen Family:

Iodine belongs to the halogen family, which includes fluorine, chlorine, bromine, and astatine. These elements share similar chemical properties.


Iodine, with its distinctive properties and diverse applications, is an elemental wonder that has permeated various aspects of our lives. From its role in medicine to its presence in everyday products, iodine's significance is evident. As we continue to explore and harness the potential of this element, its applications are likely to expand, contributing to advancements in science, health, and industry.

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