noun
Examples of silicon in a Sentence
The results of Berzelius were greatly extended by Hermann Kopp, who recognized that carbon, boron and silicon were exceptions to the law.
Scheele had done, and because he was employing a glass vessel he got "fluor acid air" (silicon fluoride).
It burns when brought into contact with chlorine, forming silicon chloride and hydrochloric acid.
Silicon fluoroform, SiHF 3, was obtained by 0.
Silicofluoric acid, H2SiF6, is obtained as shown above, and also by the action of sulphuric acid on barium silicofluoride, or by absorbing silicon fluoride in aqueous hydrofluoric acid.
The anhydrous acid is not known, since on evaporating the aqueous solution it gradually decomposes into silicon fluoride and hydrofluoric acid.
Berzelius (Jahresb., 182 5, 4, p. 91) by the action of chlorine on silicon, and is also obtained when an intimate mixture of silica and carbon is heated in a stream of chlorine and the products of reaction fractionated.
The hexachloride, Si 2 C1 61 is formed when silicon chloride vapour is passed over strongly heated silicon; by the action of chlorine on the corresponding iodocompound, or by heating the iodo-compound with mercuric chloride (C. Friedel, Comptes rendus, 18 7 1, 73, P. 497).
The alloy with 12% of silicon is white, hard and brittle.
A somewhat impure silicon (containing 90-98% of the element) is made by the Carborundum Company of Niagara Falls (United States Patents 745 122 and 842273, 1908) by heating coke and sand in an electric furnace.
It decomposes ammonia at a red heat, liberating hydrogen and yielding a compound containing silicon and nitrogen.
Silicon tetraiodide, Si14, is formed by passing iodine vapour mixed with carbon dioxide over strongly-heated silicon (C. Friedel, Comptes rendus, 1868, 67, p. 98); the iodo-compound condenses in the colder portion of the apparatus and is purified by shaking with carbon bisulphide and with mercury.
Silicon iodoform, SiHI 3, is formed by the action of hydriodic acid on silicon, the product, which contains silicon tetraiodide, being separated by fractionation.
Numerous chloro-iodides and bromoiodides of silicon have been described.
Silicon sulphide, SiS 2, is formed by the direct union of silicon with sulphur; by the action of sulphuretted hydrogen on crystallized silicon at red heat (P. Sabatier, Comptes rendus, 1880, 90, p. 819); or by passing the vapour of carbon bisulphide over a heated mixture of silica and carbon.
Alloys of magnesium and silicon are prepared by heating fragments of magnesium with magnesium filings and potassium silico-fluoride.
From the alloy containing 25% of silicon, the excess of magnesium is removed by a mixture of ethyl iodide and ether and a residue consisting of slate-blue octahedral crystals of magnesium silicide is left.
It decomposes water at ordinary temperature with evolution of hydrogen but without production of silicon hydride, whilst cold hydrochloric acid attacks it vigorously with evolution of hydrogen and spontaneously inflammable silicon hydride.
The organic derivatives of silicon resemble the corresponding carbon compounds except in so far that the silicon atom is not capable of combining with itself to form a complex chain in the same manner as the carbon atom, the limit at present being a chain of three silicon atoms. Many of the earlier-known silicon alkyl compounds were isolated by Friedel and Crafts and by Ladenburg, the method adopted consisting in the interaction of the zinc alkyl compounds with silicon halides or esters of silicic acids.
Silicon Tetramethyl, Si(CH3)4 (tetramethyl silicane), and silicon tetraethyl, Si(C2H5)4, are both liquids.
The latter reacts with chlorine to give silicon nonyl-chloride Si(C2H5)3 C2H4C1, which condenses with potassium acetate to give the acetic ester of silicon nonyl alcohol from which the alcohol (a camphor-smelling liquid) may be obtained by hydrolysis.
Silicobenzoic acid, C 6 H 5 S10.0H, results from the action of dilute aqueous ammonia on phenyl silicon chloride (obtained from mercury diphenyl and silicon tetrachloride).
The atomic weight of silicon has been determined usually by analysis of the halide compounds or by conversion of the halides into silica.
Silicon, so far as we know, behaves to metals pretty much like carbon, but our knowledge of facts is limited.
What is known as cast iron is essentially an alloy of iron proper with 2 to 6% of carbon and more or less of silicon.
Alloys of copper and silicon were prepared by Deville in 1863.
Chemically pure sand is silicon dioxide (SiO 2) or quartz, a clear transparent glass-like mineral, but as ordinarily met with, it is more or less impure and generally coloured reddish or yellowish by oxide of iron.
His contributions to inorganic chemistry were numerous, including investigations on the compounds of antimony, aluminium, silicon, &c., on the separation of nickel and cobalt, and on the analysis of mineral waters, but they are outweighed in importance by his work on organic substances.
Although at the present time a marvellous improvement has taken place all round in the quality of the carbide produced, the acetylene nearly always contains minute traces of hydrogen, ammonia, sulphuretted hydrogen, phosphuretted hydrogen, silicon hydride, nitrogen and oxygen, and sometimes minute traces of carbon monoxide and dioxide.
The presence of free hydrogen is nearly always accompanied by silicon hydride formed by the combination of the nascent hydrogen with the silicon in the carbide.
Its most important property is that it rapidly attacks glass, reacting with the silica of the glass to form gaseous silicon fluoride, and consequently it is used for etching.
Fluorides can be readily detected by their power of etching glass when warmed with sulphuric acid; or by warming them in a glass tube with concentrated sulphuric acid and holding a moistened glass rod in the mouth of the tube, the water apparently gelatinizes owing to the decomposition of the silicon fluoride formed.
Sodium is largely employed in the manufacture of cyanides and in reduction processes leading to the isolation of such elements as magnesium, silicon, boron, aluminium (formerly), &c.; it also finds application in organic chemistry.
Conspicuous examples are afforded by oxygen, carbon, boron, silicon, phosphorus, mercuric oxide and iodide.
If, according to the present method of winning the metal, a bath containing silica as well as alumina is submitted to electrolysis, both oxides are dissociated, and as silicon is a very undesirable impurity, an alumina contaminated with silica is not suited for reduction.
Two grave disadvantages were soon obvious - the limited supply of ore, and, what was even more serious, the large proportion of silicon in the reduced metal.
Commercial electrolytic aluminium of the best quality contains as the average of a large number of tests, 0.48% of silicon and 0.46% of iron, the residue being essentially aluminium itself.
Buff carried out an inquiry on the compounds of silicon in which they prepared the previously unknown gas, silicon hydride or silicuretted hydrogen.
Slow cooling, slow solidification, the presence of an abundance of carbon, and the presence of silicon, all favour the formation of graphite; rapid cooling, the presence of sulphur, and in most cases that of manganese, favour the formation of cementite.
On its way from the blast furnace to the converter or open hearth furnace the pig iron is often passed through a great reservoir called a " mixer," which acts also as an equalizer, to lessen the variation in composition of the cast iron, and as a purifier, removing part of the sulphur and silicon.
In the former case there is no later chance to remove sulphur, a minute quantity of which does great harm by leading to the formation of cementite instead of graphite and ferrite, and thus making the cast-iron castings too hard to be cut to exact shape with steel tools; in the latter case the converting or purifying processes, which are essentially oxidizing ones, though they remove the other impurities, carbon, silicon, phosphorus and manganese, are not well adapted to desulphurizing, which needs rather deoxidizing conditions, so as to cause the formation of calcium sulphide, than oxidizing ones.
The chief difficulty in the way of modifying the blastfurnace process itself so as to make it accomplish what the direct processes aim at, by giving its product less carbon and silicon than pig iron as now made contains, is the removal of the sulphur.
Moreover, the quality of the resultant steel depends upon the temperature of the process, and this in turn depends upon the proportion of silicon, the combustion of which is the chief source of the heat developed.
An excess of silicon or sulphur in the cast iron from one blastfurnace is diluted by thus mixing this iron with that from the other furnaces.
Should several furnaces simultaneously make iron too rich in silicon, this may be diluted by pouring into the mixer some low-silicon iron melted for this purpose in a cupola furnace.
Further, an important part of the silicon may be removed in the mixer by keeping it very hot and covering the metal with a rather basic slag.
This is very useful if the iron is intended for either the basic Bessemer or the basic open-hearth process, for both of which silicon is harmful.
As the essential difference between cast iron on one hand and wrought iron and steel on the other is that the former contains necessarily much more carbon, usually more silicon, and often more phosphorus that are suitable or indeed permissible in the latter two, the chief work of all these conversion processes is to remove the excess of these several foreign elements by oxidizing them to carbonic oxide CO, silica S102, and phosphoric acid P 2 0 5, respectively.
Beside this their chief and easy work of oxidizing carbon, silicon and phosphorus, the conversion processes have the harder task of removing sulphur, chiefly by converting it into calcium sulphide, CaS, or manganous sulphide, MnS, which rise to the top of the molten metal and there enter the overlying slag, from which the sulphur may escape by oxidizing to the gaseous compound, sulphurous acid, S02.
As the iron oxide is stirred into the molten metal laboriously by the workman or "puddler " with his hook or "rabble," it oxidizes the silicon to silica and the phosphorus to phosphoric acid, and unites with both these products, forming with them a basic iron silicate rich in phosphorus, called " puddling " or " tap cinder."