File Name: physical and chemical properties of silicon .zip
Allotropes Some elements exist in several different structural forms, called allotropes.
Silicon Si , a nonmetallic chemical element in the carbon family Group 14 [IVa] of the periodic table. Silicon makes up Impure silicon had already been obtained in
Silicon is a member of Group 14 IVA in the periodic table. The periodic table is a chart that shows how chemical elements are related to one another. Silicon is also part of the the carbon family. Other carbon family elements include carbon, germanium, tin, and lead. Silicon is a metalloid, one of only a very few elements that have characteristics of both metals and non-metals.
Silicon is the second most abundant element in the Earth's crust, exceeded only by oxygen. Many rocks and minerals contain silicon. Examples include sand, quartz, clays, flint, amethyst, opal, mica, feldspar, garnet, tourmaline, asbestos, talc, zircon, emerald, and aquamarine. Silicon never occurs as a free element.
It is always combined with one or more other elements as a compound. By the early s, silicon was recognized as an element. But chemists had serious problems preparing pure silicon because it bonds attaches tightly to oxygen. It took chemists many years to find out how to separate silicon from oxygen. That task was finally accomplished in by Swedish chemist Jons Jakob Berzelius Silicon's most important application is in electronic equipment. Silicon is one of the best materials from which to make transistors and computer chips.
The total weight of silicon used for this purpose is relatively small. Much larger amounts are used, for example, to make metal alloys. An alloy is made by melting and mixing two or more metals. The mixture has properties different from those of the individual metals.
In one sense, humans have always used silicon. Nearly every naturally occurring rock or mineral contains some silicon. So when ancient peoples built clay huts or sandstone temples, they were using compounds of silicon. But no one thought about silicon as an element until the nineteenth century. Then, a number of chemists tried to separate silicon from the other elements with which it is combined in the earth.
English scientist Sir Humphry Davy developed a technique for separating elements that tightly bond to each other. He melted these compounds and passed an electric current through them. The technique was successful for producing free or elemental sodium, potassium, calcium, and a number of other elements for the first time. But he failed with silicon. See sidebar on Davy in the calcium entry in Volume 1. Berzelius also tried to isolate silicon using a method similar to that of Davy's.
He mixed molten melted potassium metal with a compound known as potassium silicon fluoride K 2 SiF 6. The result was a new element—silicon. Scottish chemist Thomas Thomson suggested the name silicon, based on the Latin word for "flint," silex or silids. He added the ending -on because the new element was so much like boron and carbon. Thus, the new element's name was accepted as silicon. Some interesting studies were done on silicon over the next few years. German chemist Friedrich Wohler produced a series of compounds known as silanes.
These compounds contain silicon, hydrogen, and, sometimes, other elements. Purified silicon bar. The simplest silane is silicon tetrahydride SiH 4. This compound is also called silane. A group of compounds known as the siloxanes were produced at about the same time. The siloxanes are made up of silicon, oxygen, and an organic group. Organic compounds contain carbon. Silanes and siloxanes were not discovered in the search for the answer to any practical question. Chemists were just curious about the kinds of compounds they could make with silicon.
But many years later, chemists made some interesting discoveries. Both groups of compounds do have some very important practical uses. For example, the compounds known as silicones are a form of the siloxanes. Silicon is a metalloid, an element with properties of both metals and non-metals.
Silicon exists in two allotropic forms. Allotropes are forms of an element with different physical and chemical properties. One allotrope is in the form of shiny, grayish-black, needle-like crystals, or flat plates. The second allotrope has no crystal structure and usually occurs as a brown powder. Its density is 2. Silicon has a hardness of about 7 on the Mohs scale.
The Mohs scale is a way of expressing the hardness of a material. It runs from 0 for talc to 10 for diamond. Silicon is a semiconductor. A semiconductor is a substance that conducts an electric current better than a non-conductor—like glass or rubber—but not as well as a conductor—like copper or aluminum. Semiconductors have important applications in the electronics industry. Silicon is a relatively inactive element at room temperature.
It does not combine with oxygen or most other elements. Water, steam, and most acids have very little affect on the element. At higher temperatures, however, silicon becomes much more reactive. In the molten melted state, for example, it combines with oxygen, nitrogen, sulfur, phosphorus, and other elements. It also forms a number of alloys very easily in the molten state. Silicon is the second must abundant element in the Earth's crust.
Its abundance is estimated to be about It ranks second only to oxygen. Some authorities believe that more than 97 percent of the crust is made of rocks that contain compounds of silicon and oxygen.
Silicon has been detected in the Sun and stars. It also occurs in certain types of meteorites known as aerolites or "stony meteorites. Silicon never occurs as a free element in nature. It always occurs as a compound with oxygen, magnesium, calcium, phosphorus, or other elements. The most common minerals are those that contain silicon dioxide in one form or another. These are known as silicates. It also occurs in certain types of meteorites.
There are three naturally occurring isotopes of silicon: silicon, silicon, and silicon Isotopes are two or more forms of an element. Isotopes differ from each other according to their mass number. The number written to the right of the element's name is the mass number. The mass number represents the number of protons plus neutrons in the nucleus of an atom of the element.
The number of protons determines the element, but the number of neutrons in the atom of any one element can vary. Each variation is an isotope. Five radioactive isotopes of silicon are known also. A radioactive isotope is one that breaks apart and gives off some form of radiation.
Radioactive isotopes are produced when very small particles are fired at atoms. These particles stick in the atoms and make them radioactive. Silicon is prepared by heating silicon dioxide with carbon. Carbon replaces the silicon in the compound. The silicon formed is 96 to 98 percent pure.
Many applications of silicon require a very pure product. Methods have been developed to produce silicon that is at least This form of silicon is called hyper-pure silicon.
Perhaps the best known use of silicon is in electronic devices. Hyperpure silicon is used in transistors and other components of electronic devices. It is also used to make photovoltaic solar cells, rectifiers, and parts for computer circuits.
Silicon material properties Silicon wafer properties 1. Crystal properties 1. Properties 2. Band structure properties 2. Typical Sizes of Semiconductor Wafers 3. Thermal properties 3. Wafer Flats 4.
Silicon metal is a grey and lustrous semi-conductive metal that is used to manufacture steel, solar cells, and microchips. Silicon is the second most abundant element in the earth's crust behind only oxygen and the eighth-most common element in the universe. Nearly 30 percent of the weight of the earth's crust can be attributed to silicon. The element with atomic number 14 naturally occurs in silicate minerals, including silica, feldspar, and mica, which are major components of common rocks such as quartz and sandstone. A semi-metal or metalloid , silicon possesses some properties of both metals and non-metals. Like water - but unlike most metals - silicon contracts in its liquid state and expands as it solidifies. It has relatively high melting and boiling points, and when crystallized forms a diamond cubic crystal structure.
Silicon is a chemical element with the symbol Si and atomic number It is a hard, brittle crystalline solid with a blue-grey metallic lustre, and is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic table: carbon is above it; and germanium , tin , and lead are below it. It is relatively unreactive. Its oxides form a family of anions known as silicates. Silicon is the eighth most common element in the universe by mass, but very rarely occurs as the pure element in the Earth's crust.
The Properties and Uses of Silicon Metal
Silicon is a member of Group 14 IVA in the periodic table. The periodic table is a chart that shows how chemical elements are related to one another. Silicon is also part of the the carbon family. Other carbon family elements include carbon, germanium, tin, and lead.
Moreover, pentacoordinated and hexacoordinated silicon compounds are also known. Natural silicon contains Apart from those stable natural isotopes, various radiactive artificial isotopes are known.
What is the intricate orb pictured below? It is the greatly magnified skeleton of single-celled ocean organisms called radiolaria singular radiolarian. The skeleton is made of an element that is extremely common on Earth. In fact, it is the second most abundant element in Earth's crust. It is also one of the most common elements in the entire universe.
Я слышал, она его уже достала. Мидж задумалась.
Silicon - Si
ГЛАВНАЯ РАЗНИЦА МЕЖДУ ЭЛЕМЕНТАМИ, ОТВЕТСТВЕННЫМИ ЗА ХИРОСИМУ И НАГАСАКИ Соши размышляла вслух: - Элементы, ответственные за Хиросиму и Нагасаки… Пёрл-Харбор. Отказ Хирохито… - Нам нужно число, - повторял Джабба, - а не политические теории. Мы говорим о математике, а не об истории. Соши замолчала. - Полезный груз? - предложил Бринкерхофф.
Если Танкадо не понял, что стал жертвой убийства, зачем ему было отдавать ключ. - Согласен, - сказал Джабба. - Этот парень был диссидентом, но диссидентом, сохранившим совесть. Одно дело - заставить нас рассказать про ТРАНСТЕКСТ, и совершенно другое - раскрыть все государственные секреты.
Лифт, соединяющий шифровалку с основным зданием, получал питание из главного комплекса, и оно действовало, несмотря на отключение питания шифровалки. Стратмору, разумеется, это было хорошо известно, но даже когда Сьюзан порывалась уйти через главный выход, он не обмолвился об этом ни единым словом. Он не мог пока ее отпустить - время еще не пришло. И размышлял о том, что должен ей сказать, чтобы убедить остаться. Сьюзан кинулась мимо Стратмора к задней стене и принялась отчаянно нажимать на клавиши. - Пожалуйста, - взмолилась .
and Tsmots Volodymyr. Chapter 4 Structure and Properties of Dislocations in Silicon 57 Physical and chemical approaches for controlling the band gap of crystalline silicon  (noanimalpoaching.org).  T. Hou.
Сеньор Ролдан забирал большую часть ее заработка себе, но без него ей пришлось бы присоединиться к бесчисленным шлюхам, что пытаются подцепить пьяных туристов в Триане. А у ее клиентов по крайней мере есть деньги. Они ее не бьют, им легко угодить. Росио натянула ночную рубашку, глубоко вздохнула и открыла дверь в комнату.
Escortes Belen, - ответил мужчина. И снова Беккер изложил свою проблему: - Si, si, senor. Меня зовут сеньор Ролдан. Буду рад вам помочь.
Ненависть в его сердце уступила место преданности Будде. Еще через четыре месяца Энсей Танкадо приступил к работе в Отделении криптографии Агентства национальной безопасности США. Несмотря на солидный заработок, Танкадо ездил на службу на стареньком мопеде и обедал в одиночестве за своим рабочим столом, вместо того чтобы вместе с сослуживцами поглощать котлеты из телятины и луковый суп с картофелем - фирменные блюда местной столовой. Энсей пользовался всеобщим уважением, работал творчески, с блеском, что дано немногим. Он был добрым и честным, выдержанным и безукоризненным в общении.