Selenium - TablaPe

Uses and Properties

Image Explanation

Selenium disulfide shampoos can be an effective solution for dandruff and seborrheic dermatitis, thanks to their antifungal and anti-inflammatory properties.

Appearance

A semi-metal that can exist in two forms: as a silvery metal or as a red powder.

Uses

Selenium: Unveiling the Diverse Applications of a Vital Trace Element

Selenium, a trace element with atomic number 34 and symbol Se, might not be as famous as some of its chemical counterparts, but it plays a crucial role in various aspects of human and environmental health. Selenium is a versatile element with applications that extend from nutrition and medicine to industry and the environment. In this article, we will explore the myriad uses and significance of selenium in our lives, shedding light on its diverse applications.

Nutrition and Dietary Supplements

One of the most well-known uses of selenium is its role in human nutrition. Selenium is an essential mineral, meaning the human body requires it for optimal health. It acts as a cofactor for various enzymes, particularly those involved in the body's antioxidant defense system. Selenium is found in a variety of foods, including seafood, meat, nuts, and grains. Dietary supplements are also commonly used to ensure individuals meet their recommended daily intake of selenium. Adequate selenium intake supports various bodily functions, including immune system health and thyroid function.

Antioxidant Properties

Selenium's role as a powerful antioxidant is critical for maintaining cellular health. It works in synergy with other antioxidants, such as vitamin E, to neutralize harmful free radicals in the body. This antioxidative action helps protect cells from oxidative stress, which can lead to various health issues, including chronic diseases and premature aging.

Medicine and Healthcare

Selenium's potential health benefits have led to its inclusion in some medical treatments. It has been studied for its role in cancer prevention and therapy. Selenium supplements have been investigated for their potential to reduce the risk of certain cancers, such as prostate cancer. Additionally, selenium is a component of some drugs used in medical imaging and diagnosis.

Environmental Remediation

Selenium is used in environmental remediation to mitigate the impact of pollution, particularly in water bodies. Selenium can be toxic to aquatic life at elevated levels, and its release into the environment from industrial activities can have harmful ecological effects. Various methods, such as selenium treatment ponds, are employed to capture and remove selenium from wastewater to prevent its detrimental impact on ecosystems.

Metallurgy and Glassmaking

Selenium is used in metallurgy, primarily for refining certain metals, such as copper and lead. It acts as a deoxidizing agent, helping to remove impurities and improve the quality of the final product. Selenium is also used in glassmaking, where it decolorizes glass and reduces the greenish tint often seen in untreated glass.

Electronics and Photovoltaics

Selenium's semiconductor properties make it valuable in electronics. It is used in photodetectors and solar cells. Selenium photovoltaic cells are known for their low-cost and ease of production, making them suitable for specific applications, such as solar-powered calculators and traffic signals.

Agriculture and Livestock Nutrition

Selenium is essential not only for human health but also for the health of livestock. Selenium deficiency in animals can lead to various health issues, including muscle diseases and decreased immune function. Selenium supplements are used in animal feeds to ensure that livestock receive adequate nutrition and maintain good health. Selenium is also utilized in soil treatment in regions with selenium-deficient soils to improve crop selenium content.

Glass Fiber Production

In the manufacture of optical fibers, selenium is employed to increase the refractive index of the glass core. This enhances the efficiency of data transmission in fiber optic communication systems. The use of selenium-doped glass fibers allows for faster and more reliable data transfer over long distances.

Geological Exploration

Selenium is used as a tracer in geological exploration to study the movement of materials and substances in the Earth's crust. By introducing a small amount of selenium into a sample and tracking its behavior, geologists gain insights into geological processes and the movement of materials in the Earth's layers.

Aerospace Industry

Selenium is used in certain aerospace applications, including the production of high-performance lubricants and hydraulic fluids. These applications benefit from selenium's anti-wear and anti-corrosion properties, helping to ensure the reliability and longevity of aerospace systems.

Conclusion

Selenium, often overshadowed by more prominent elements, is a trace mineral with a multitude of applications and significance in our lives. From its role in nutrition and healthcare to its importance in industry, environment, and technology, selenium's versatility and impact are far-reaching.

As we continue to explore its uses and benefits, it becomes increasingly clear that selenium is an element that contributes to both our well-being and the advancement of various fields. Its antioxidative properties, role in nutrition, and wide-ranging applications in industry and science underscore the diverse ways in which selenium enriches our world.

History

Elements and Periodic Table History

Selenium, a chemical element represented by the symbol Se and atomic number 34, has a rich and intriguing history that spans centuries. From its discovery as an element to its diverse applications in various fields, selenium's journey has been marked by scientific curiosity, breakthroughs, and its role in improving human health, industry, and technology. In this article, we will delve into the captivating history of Selenium, uncovering its evolution and impact on our world.

The Discovery of Selenium

Selenium was discovered in 1817 by the Swedish chemist Jöns Jacob Berzelius, who was conducting experiments to purify sulfuric acid. During this process, he observed a red substance that appeared alongside the sulfuric acid. Berzelius recognized the unknown substance as a new element and named it "selenium" after the Greek word "selēnē," meaning "moon." This name was chosen due to the element's resemblance to tellurium, which was named after the Earth.

Early Observations and Challenges

Berzelius's discovery of selenium opened the door to further research and experimentation. Early chemists observed selenium's unique properties, such as its ability to exist in multiple allotropic forms. Selenium's allotropic forms exhibit distinct physical properties, which presented a challenge in understanding and working with the element.

Selenium in Photography

One of the earliest practical applications of selenium was in photography. In the 1870s, American physicist Willoughby Smith discovered that selenium's electrical resistance changed when exposed to light. This discovery laid the foundation for selenium's use in light meters and light-sensitive cells for early photographic exposure meters, known as selenium photovoltaic cells. These cells were instrumental in photography, helping photographers determine the proper exposure for their shots.

Selenium in Electronics

Selenium's semiconductor properties became a focus of research in the mid-20th century. Selenium rectifiers, which allowed the flow of electricity in one direction while blocking it in the other, were used in early radio and electronic equipment. However, selenium rectifiers had limitations, such as low efficiency and the generation of heat during operation. As a result, these rectifiers were gradually replaced by more efficient silicon diodes.

Selenium in Biology and Nutrition

Selenium's importance in biology and human nutrition began to emerge in the mid-20th century. Researchers discovered that selenium was an essential trace element required by animals for good health. Selenium deficiency in livestock was found to cause diseases, such as white muscle disease in cattle and exudative diathesis in poultry. This led to the introduction of selenium supplements in animal feed to prevent deficiency-related issues.

In the 1950s, the significance of selenium in human nutrition was recognized. Selenium was identified as an essential component of the enzyme glutathione peroxidase, which plays a crucial role in protecting cells from oxidative damage. Selenium's antioxidant properties are integral to maintaining cellular health.

The Role of Selenium in Health and Disease Prevention

Research in the late 20th and early 21st centuries has shed light on the vital role of selenium in human health and its potential role in disease prevention. Selenium is known to support the immune system, reduce inflammation, and protect against oxidative stress, which can contribute to chronic diseases such as cancer and heart disease.

Selenium's potential role in cancer prevention has been a subject of investigation. Some studies suggest that adequate selenium intake may reduce the risk of certain cancers, such as prostate, lung, and colorectal cancer. However, the relationship between selenium and cancer risk is complex, and more research is needed to fully understand its impact.

Selenium in Environmental Remediation

Selenium's presence in the environment can have both positive and negative impacts. While selenium is an essential nutrient for various organisms, excessive selenium in ecosystems can be toxic, leading to adverse effects on aquatic life. In regions where industrial activities release selenium into water bodies, environmental remediation methods are employed to reduce selenium's ecological impact.

Modern Applications of Selenium

Selenium continues to find diverse applications in the modern world. It is used in photovoltaic cells for specific applications where cost-effectiveness and ease of production are important, such as in solar-powered calculators and traffic signals. In addition, selenium is used in the aerospace industry to create high-performance lubricants and hydraulic fluids due to its anti-wear and anti-corrosion properties.

Selenium's history is a testament to the evolving understanding of chemical elements and their applications. From its discovery in the 19th century to its diverse roles in modern society, selenium has left an indelible mark on various fields, including photography, electronics, biology, and health.

As we continue to explore its uses and benefits, selenium remains a dynamic and indispensable element, contributing to the advancement of science, technology, and human well-being. Its journey from the moon-inspired name to its vital role in health and industry exemplifies the intricate interplay between scientific discovery and practical applications in our ever-changing world.

Atomic Data

Atomic Radiues, Non-bonded (A): 1.90

Electron Affinity (kJ mol-1): 194.965

Covalent Radiues (A): 1.18

Electronegativity (Pauling Scale): 2.55

Ionisation Energies (kJ mol-1)	1st	2nd	3rd	4th	5th	6th	7th	8th
	940.963	2044.52	2973.717	4143.563	6589.9	7882.9	14993.8	-

Oxidation States and Isotopes

Common oxidation states 6, 4, -2

Isotope	Atomic Mass	Natural Abundance	Half Life	Mode of Decay
⁷⁴Se	73.922	0.89	> 5.5 x 10¹⁸ y	EC-EC
⁷⁶Se	75.919	9.37	-	-
⁷⁷Se	76.920	7.63	-	-
⁷⁸Se	77.917	23.77	-	-
⁸⁰Se	79.917	49.61	-	-
⁸²Se	81.917	8.73	> 9.5 x 10¹⁹ y	β-β-

Supply Risk

Relative Supply Risk: 7.1

Crustal Abundance (ppm): 0.13

Recycle Rate (%): <10

Production Conc.(%) : 35

Top 3 Producers:
1) Japan
2) Germany
3) Belgium

Top 3 Reserve Holders:
1) Russia
2) Chile
3) Peru

Substitutability: Unknown

Political Stability of Top Producer: 76.9

Political Stability of Top Reserve Holder: 18.4

Pressure and Temperature Data

Specific Heat Capacity: 321

Shear Modulus: Unknown

Young Modulus: Unknown

Bulk Modulus: 8.3

Pressure 400k	Pressure 600k	Pressure 800k	Pressure 1000k	Pressure 1200k	Pressure 1400k	Pressure 1600k	Pressure 1800k	Pressure 2000k	Pressure 2200k	Pressure 2400k
-	-	-	-	-	-	-	-	-	-	8.3

Podcast

Transcript :

Selenium is a chemical element that is closely related to tellurium and sulfur. It belongs to the chalcogen family and has a number of allotropic forms. Some of the most common are the gray crystalline metal and the red amorphous powder. The behavior of selenium in the environment depends on the interaction with other compounds. For instance, selenium is most likely to enter the air through coal combustion. This means that people who live in the vicinity of an industrial site may have higher exposure to selenium. However, the amount of selenium in the air is usually not harmful to organisms.

Selenium is one of the most important elements in the human body. It plays an essential role in the protection of the body against free radicals, which are harmful to the body. The average human body contains about 14 mg of selenium.

Despite its importance, selenium is considered to be a toxic element. The effects of selenium poisoning can lead to serious diseases, including anemia, blindness, and bone stiffness.

There are various forms of selenium, including inorganic compounds and organic compounds. This substance is known to interact with several metals and forms ring-shaped molecules with a red color. The amount of selenium in the environment is highly dependent on the climate of the area. People living in areas where farming, metal industry, and hazardous waste-sites are prevalent, will experience a higher level of exposure to selenium.

Selenium is an important component in several enzymes. For example, it is a component of the active center of glutathione peroxidase and iodothyronine deiodinase. These enzymes are vital for cell function in many animals. The element has six naturally occurring isotopes. Two of these are radioactive. One of these is known by the name selenocitrate, and the other is selenic acid. Selenic acid is a strong oxidant that is easily reduced.

Selenium was only officially discovered in the 19th century. Before that, it was known only through medieval Spanish alchemist Arnold of Villanova. He had noted a mysterious substance that had a red color.

Selenium is a naturally occurring mineral and occurs in the environment in varying quantities. This element is most abundant in sulfide ores. It is found in the soil, water, and air of many locations and is found in a variety of forms. The most common forms of selenium are crystalline and amorphous. Typically, Selenium is found in combination with silver minerals. This element is most often derived from selenide in sulfide ores.

It is most commonly formed as a by-product of refining metal sulfide ores. During smelting, selenium compounds are released to the air and water. In addition to releasing these substances to the air, it may enter the water via aqueous solutions such as anti-dandruff shampoos and cleaning chemicals.

The properties of selenium vary depending on the form and the atomic mass. It has a density of 4.5 grams per cc. Compared to the typical metals, it conducts electricity much better. This element, is an essential micronutrient for all living things. However, it is toxic in high concentrations. Moreover, large doses of it can lead to reproductive failure and this element is a very reactive element. This means that it can react with a number of metals to form selenides, which are inorganic compounds.

As an inorganic compound, selenium is soluble in water. When it comes into contact with nitric acid, it dissolves and combines with oxygen to form selenite. In its most common form, it is a red crystalline material that, in the presence of light, conducts electricity better.

Selenium has an electronegativity of 2.25 on the Pauling scale. Although this element is considered non-metal. Although selenium has properties similar to sulfur, it is less allotropic. This means that it can be formed into a number of different shapes. For example, it can be found as an amorphous powder that is red, brown, and even black. When heated, it can turn black.

Selenium is a fairly reactive element. It is commonly combined with copper, silver and sulfide minerals. However, it can be prepared as a pure metallic gray crystalline substance.

Selenium has many different uses. It was used to treat certain types of illnesses and is also used to make plastics. This element is used in metal alloys, glass and photocells, photoelectric devices, and semiconductors. Selenium is also used in preparing red enamels for ceramics and steel. It is used as a catalyst in a variety of organic chemical reactions. This element is also a component of decolorized glass. It has the ability to change the color of glass to a deep red or light orange.

A variety of devices are serving from Selenium properties such as, X-ray systems, printers, photocopiers and telephotographic apparatus. Also, it has been extensively used in electronic devices, for example, it is a component in the grey allotrope, which is used in rectifiers in radio and television sets. It is also a common ingredient in vulcanizing agents for rubber products. Aside from these applications, Selenium is also used in a number of food supplements because it has been linked to cancer prevention.

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References

W. M. Haynes, ed., CRC Handbook of Chemistry and Physics, CRC Press/Taylor and Francis, Boca Raton, FL, 95th Edition, Internet Version 2015, accessed December 2014.

Tables of Physical & Chemical Constants, Kaye & Laby Online, 16th edition, 1995. Version 1.0 (2005), accessed December 2014.

J. S. Coursey, D. J. Schwab, J. J. Tsai, and R. A. Dragoset, Atomic Weights and Isotopic Compositions (version 4.1), 2015, National Institute of Standards and Technology, Gaithersburg, MD, accessed November 2016.

T. L. Cottrell, The Strengths of Chemical Bonds, Butterworth, London, 1954.

John Emsley, Nature’s Building Blocks: An A-Z Guide to the Elements, Oxford University Press, New York, 2nd Edition, 2011.

Thomas Jefferson National Accelerator Facility - Office of Science Education, It’s Elemental - The Periodic Table of Elements, accessed December 2014.

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