Constantly my chemistry teacher encourages us to shrink down to the size of an atom and see the world from a subatomic state. I encourage people to imagine themselves as an atom, as crazy as it seems, and direct their attention to the neoteric world around themselves. One may come to notice that atoms of dissimilar elements have many comparable qualities when looking at them in this light. Any element that one could view is sure to strike one into a state of awe; however, selenium is a particular element that has an alluring history, intriguing characteristics, and an impressive role in society.
Selenium was discovered by Jons Jacob Berzelius at Stockholm in 1817 and is named after the Greek word for the moon, Selene (“Selenium”). Jons discovered the element in the bottom of a chamber where sulfuric acid was being produced (“Selenium”). Upon his first impression, Berzelius believed that Selenium was tellurium because of the strong smell of radishes that the element had emitted once heated (“Selenium”). Of course, he eventually found that it was indeed a new element. He made remarks of the elements properties and noted that the element had many analogous traits with both sulfur and tellurium (“Selenium”).
This element affected Berzelius physically as well. Working with the element caused him to have bad breath (“Selenium”). Although his new found halitosis was an inconvenience, the discovery of selenium is very important to the periodic table today. Between tellurium and sulfur, one may find selenium. This element belongs to group 6 (VIA group) and its placement between sulfur and tellurium was no mistake (“Chemical”). Selenium is classified as a chalcogen along with other elements such as oxygen, sulfur, and tellurium (“Selenium”).
Selenium is also considered a non-metal (“Chemical”). The placement of an element on the periodic table is mandatory to the element’s physical properties and composition. Selenium has many physical properties because it is rather unique. It also contains several allotropic forms. Under normal atmospheric conditions, Selenium is a solid (“Chemical”). Selenium appears as a red, gray, or black substance when it is solid (“Chemical”). Selenium also has several other allotropic forms, but only three are recognized though there are claims that more have occurred (“Chemical”).
Depending on the color or form of Selenium, its melting points may change. Red selenium, in a dust like state, has a melting point of 221 degrees celsius (“Chemical”). Gray selenium, in a reflective metallic form, has a melting point 220. 5 degrees celsius (“Chemical”). Black selenium, in an amorphous form, has a melting point at 180 degrees celcius. Although the melting points vary, the boiling point of this element does not. At 685 degrees celsius, the element will boil regardless of color or form (“Chemical”).
In addition to its appearance selenium does have an odor, as previously stated in Berzelius’ discovery, that can be described as radishes or burning horseradish (“Chemical”). Selenium also has an unusual conductivity. It has good photovoltaic and photoconductive properties which mean that when different amounts of photons that are projected at selenium, the conductivity of electricity changes (“Water Treatment Solutions. “). Along with conductivity, selenium is sometimes used as a rectifier to change AC currents to DC currents (“Water Treatment Solutions. “).
Furthermore, selenium has a density of 4. 09 grams per cubic centimeter (“The Element Selenium”). When it comes to selenium’s hardness, it is measured at a 2 on Mohs scale (Mineral Info). In addition to hardness, malleability and ductility are non-existent in selenium since it occurs as a powder like state. All of the physical properties that transpire in selenium are dependent to the element’s nuclear properties. Selenium’s nuclear properties include a slew of isotopes.
The six stable isotopes of selenium are 745e, 765e, 77Se, 785e, 80Se, and 82Se (Chemical). “These isotopes occur naturally with approximate abundances of 0. 87, . 02, 7. 58, 23. 52, 49. 82, and 9. 19%. ” (Chemical) Artificial isotopes have also been created by using the neutron activation method. Neutron activation essentially determines the concentration of an element in materials (“For Chemical Analysis”). One important isotope that has been created is the gamma-emitting 75se (Chemical). The nuclear properties of selenium are an essential part of its attributes, but the chemical properties are just as germane. The chemical properties of selenium vary depending on the reactants that are interacting with the different allotropes of selenium.
However, the following reactions describe the most common state of selenium. When selenium is exposed to air it burns and creates a blue flame (“Chemistry of Selenium”). Halides are another reactant that causes selenium to burn. When mixed with fluorine, F2, selenium burns to form the selenium hexafluoride (“Chemistry of Selenium”). Selenium also reacts with chlorine and bromine to form diselenium dichloride, Se2C12 and diselenium dibromide, Se2Br2 (“Chemistry of Selenium”). Selenium does not react with dilute non-oxidizing acids as well as bases (“Selenium: Reactions”).
Another molecule that selenium does not react to is water; however, it is insoluble in water (“Chemical”). As one can clearly see physical, chemical, and nuclear attributes are very important to the composition of selenium, however, one may ask what selenium is used for in our society and where does it come from. Selenium is a naturally occurring element (“Water Treatment Solutions”). It is found in minerals such as eucairite (CuAgSe), crooksite (CuthSe) and clausthalite (PbSe), but it can also obtained as a byproduct during the creation of copper (“The Element Selenium”).
The origin of an element is incumbent to understanding selenium, but how we utilize its abilities in our culture. Selenium contributes to many consumer products that one uses to complete daily tasks. Because of the previously stated photovoltaic and photoconductive properties of selenium, it is used a myriad of electronics (“Water Treatment Solutions”). Another use of this element is to remove color from glass and give a red color to glasses and other glazes (“Water Treatment Solutions”).
In addition to its other functions, selenium is found in animal feeds and food supplements; approximately 15% of sodium selenite is added to the supplements (“Water Treatment Solutions”). Other applications range from photocopying, in toning photographs, to antidandruff shampoos (“Water Treatment Solutions”). Selenium does form some inorganic compounds, but few of them are of use to the consumer world (“Water Treatment Solutions”). Although isotope 75Se has been used in medical technology because of its gamma-emitting properties (“Chemical”). Many of the products previously stated are important to the world we have today.
Since selenium is found in products like printers, photography, shampoos, and animal feed, it is necessary to uphold the demand of these products; an important factor of the creation of these products is the manufacture and processing of the element to make it disposable. The production of selenium commonly uses the extraction of the byproduct selenium dioxide from the purification of copper (“Selenium Production”). The process begins by oxidizing the copper with sodium carbonate to produce selenium dioxide (“Selenium Production”). Next the selenium dioxide is added to water to make the solution an acid (“Selenium Production”).
The acid is then “bubbled” with sulfur dioxide to change the previous selenious acid into selenium (“Selenium Production”). This reaction causes it to take on the form of the red powder like substance opposed to its other allotropic forms (“Selenium Production”). Once it has reached this stage it can then be rapidly melted into the black glass-like form (“Selenium Production”). The manufacture of selenium can be very thorough and does have a pecuniary effect on the purchase of the element. Selenium is a rather limited element of this planet and is even more limited than silver (“Water Treatment Solutions”).
There are approximately 40 known minerals which contain selenium, and some may be composed of up to 30% selenium (“Water Treatment Solutions”). Many of these minerals are scarce and tend to occur in sulfides of metals such as copper, zinc, and lead. There are three main countries that produce selenium; Canada, the United States of America, and Russia. Production on a worldwide scale comes to 1500 tons of selenium per year, given 150 tons are from previously recycled wastes (“Water Treatment Solutions”). Currently, selenium costs around $300 per pound (“#34 – Selenium”).
The absorption of all this information can lead to the question of selenium’s beneficial or detrimental effect on society. Selenium is very beneficial to today’s society. Although it may be argued that in large amounts selenium can be deadly to humans, small amounts are used in a bountiful amount of products. Whenever we copy photos, tone photographs, play on our phones, or even wash our hair, this element makes these tasks possible with ease. This product also generates cash flow to our economy because we are one of the top major producers and sellers of selenium.
Overall this element is constructive to our society in both a consumer manner and a pecuniary presence. Ultimately selenium has a smelly ancestry, innumerable properties, and an unequivocal role in our community. This element is unique in many senses, but it also shares analogous qualities with the elements it resides near on the periodic table. Whether selenium is in a dust-like state, reacting to halides, or conducting electricity under the influence of different amount of photons, it is necessary that this element exist, help us in create everyday items, and better understand the metaphysical world around us.