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The element silicon

Silicon is a chemical element with the atomic number 14. In the periodic table of elements it abbreviated as “Si” and is one of the classic metalloids. Pure silicon is grey-black with a shiny gloss typical for metals. Due to its chemical properties it is used in industry for the production of electronic components (e.g. microchips and processors).

But there are many more additional industrial uses. As silicates, minerals, or silicon dioxide, mainly quartz, it is used for the production of glasses, cement and ceramic and represents the main component of these products.

Silicon deposits

The natural deposits on the earth are very large. Silicon is, after oxygen, the second most frequent element on the earth’s crust and is, with approximately 28 percent of the earth’s mass, omnipresent. Even in space silicon is the 8th most frequent element by weight. The earthlike planets all consist to the major part of silicon. It can be found in dust, sand, stone and planet mass in various forms of silicates and silicon dioxide compounds.

Silicon reacts very easily with oxygen, so that on earth it rarely occurs in its pure form. It mainly occurs as highly stable silicate minerals and silicon oxides. Sand is ubiquitous, consists of silicon dioxide, and, because of its hardness, the chemical resistance and resistance to weather, it exists in the upper earth’s crust. Together with the addition of the most varied substances in its pure form, silicon forms characteristic quartz which are known as various precious stones (e.g. amethyst, rose quartz, agate and opal). The most precious quartz are the precious stones emerald and aquamarine. Together with many metals silicon forms silicates (salts of silicic acid Si(OH)4). The earth’s crust consists to 90%, and the earth’s mantle almost completely, of silicates and is a substance in stones. The most frequent silicates are feldspar followed by minerals such as mica, clays, slate, sandstone, garnet etc...

Silicon not only occurs in a solid form on earth. In the world’s oceans the major part of the natural silicon is dissolved in monomeric silicic acid. One names oxygen acids of silicon silicic acids. The simplest acid is the mono silicic acid (orthosilicic acid) and this can be found in all bodies of water, also in drinking water as well as in animal and vegetable body fluids. The concentration of dissolved silicon in the water depends on the geographic and geological environmental characteristics, since it enters the water and drinking water as a result of the weathering of stone and earth.

Silicon in nature

Silicon occurs in nature in large quantities as silicon compounds. It is, however, only ingested and utilised by very few living creatures. These organisms form structures containing silicates, among these living organisms are rock algae (diatoms), radiolarian and some kinds of sponges. With the aid of special enzymes they form exoskeletons containing silicon oxide. In the world of plants there are also breeds that make use of the special properties of silicon. This one finds in horsetail and bamboo plants a high silicon dioxide content in the leaves and the stems. The plants form a silicon dioxide structure, which makes the plants stable without any ill effects on the flexibility.

Essentially silicon is absorbed by all plants during growth and stored in the plant. Many plants accumulate silicon out of the ground or from earthy solutions and use it as structure forming element e.g. for strengthening the plant stems. Especially in cereals and grasses high silicon contents can be found. When the raw products are processed to food a large part of the silicon content is removed, so that this is no longer available.

Silicon in the human body

The human body contains about 1 to 2 g of silicon. It is thus, after minerals such as iron and zinc (physiologically important trace elements), the third most frequent trace element in the body. Despite the high proportion of silicon in the body its has not finally been clarified what its function is in the human body. Initially the opinion was that silicon was a mineral without any function in the organism. Studies on animals, that were performed starting in the seventies, however, show changes in the area of the connective tissue and bone tissue as a result of a diet related silicon deficiency. Silicon can only be introduced to the body as nutrition, for this reason one speaks of an essential mineral. The body therefore relies on nutrition with sufficient silicon in a form that the organism can utilise.