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|Section2= |Section7= |Section8= }} Silicon monoxide is the chemical compound with the formula SiO where silicon is present in the oxidation state +2. In the vapour phase it is a diatomic molecule. It has been detected in stellar objects〔Gibb, A.G.; Davis, C.J.; Moore, T.J.T., A survey of SiO 5 → 4 emission towards outflows from massive young stellar objects. Monthly Notices of the Royal Astronomical Society, 382, 3, 1213-1224. , .〕 and it has been described as the most common oxide of silicon in the universe.〔Peter Jutzi and Ulrich Schubert (2003) ''Silicon chemistry: from the atom to extended systems''. Wiley-VCH ISBN 3-527-30647-1.〕 When SiO gas is cooled rapidly, it condenses to form a brown/black polymeric glassy material, (SiO)''n'', which is available commercially and used to deposit films of SiO. Glassy (SiO)''n'' is air- and moisture-sensitive. Its surface readily oxidizes in air at room temperature, giving an SiO2 surface layer that protects the material from further oxidation. However, (SiO)''n'' irreversibly disproportionates into SiO2 and Si in a few hours between 400 and 800°C, and very rapidly between 1,000 and 1,440°C, although the reaction does not go to completion.〔W. Hertl and W. W. Pultz, ''J. Am. Ceramic Soc''. Vol. 50, Issue 7, (1967) pp. 378-381.〕 ==Formation of SiO== The first precise report on the formation of SiO was in 1887〔J. W. Mellor "A Comprehensive Treatise on Inorganic and Theoretical Chemistry" Vol VI, Longmans, Green and Co. (1947) p. 235.〕 by the chemist (Charles F. Maybery ) (1850–1927) at the (Case School of Applied Science ) in Cleveland. Maybery claimed that SiO formed as an amorphous greenish-yellow substance with a vitreous luster when silica was reduced with charcoal in the absence of metals in an electric furnace.〔C. F. Maybery ''Amer. Chem. Journ.'' 9, 11, (1887).〕 The substance was always found at the interface between the charcoal and silica particles. By investigating some of the chemical properties of the substance, its specific gravity, and a combustion analysis, Maybery deduced that the substance must be SiO. The equation representing the partial chemical reduction of SiO2 with C can be represented as: : ⇌ Complete reduction of SiO2 with twice the amount of carbon yields elemental silicon and twice the amount of carbon monoxide. In 1890, the German chemist Clemens Winkler (the discoverer of germanium) was the first to attempt to synthesize SiO by heating silicon dioxide with silicon in a combustion furnace.〔C. Winkler ''Ber''. 23, (1890) p. 2652.〕 : ⇌ However, Winkler was not able to produce the monoxide since the temperature of the mixture was only around 1000°C. The experiment was repeated in 1905 by (Henry Noel Potter ) (1869–1942), a Westinghouse engineer. Using an electric furnace, Potter was able to attain a temperature of 1700°C and observe the generation of SiO.〔 (Potter ) also investigated the properties and applications of the solid form of SiO.〔U.S. Patent 182,082, July 26, 1905.〕〔E. F. Roeber H. C. Parmelee (Eds.) (Electrochemical and Metallurgical Industry, Vol. 5 ) (1907) p. 442.〕 Because of the volatility of SiO, silica can be removed from ores or minerals by heating them with silicon to produce gaseous SiO in this manner.〔 However, due to the difficulties associated with accurately measuring its vapor pressure, and because of the dependency on the specifics of the experimental design, various values have been reported in the literature for the vapor pressure of SiO (g). For the pSiO above molten silicon in a quartz (SiO2) crucible at the melting point of silicon, one study yielded a value of 0.002 atm.〔"Handbook of Semiconductor Silicon Technology," W. C. O'Mara, R. B. Herring, L. P. Hunt, Noyes Publications (1990), p. 148〕 For the direct vaporization of pure, amorphous SiO solid, 0.001 atm has been reported.〔J. A. Nuth III, F. T. Ferguson, The Astrophysical Journal, 649, 1178-1183 (2006)〕 For a coating system, at the phase boundary between SiO2 and a silicide, 0.01 atm was reported.〔"High-Temperature Oxidation-Resistant Coatings ," National Academy of Sciences/National Academy of Engineering (1970), p. 40〕 Silica itself, or refractories containing SiO2, can be reduced with H2 or CO at high temperatures, e.g.:〔Charles A. (2004) Schacht Refractories handbook. CRC Press, ISBN 0-8247-5654-1.〕 :(g) ⇌ As the SiO product volatilizes off (is removed), the equilibrium shifts to the right, resulting in the continued consumption of SiO2. Based on the dependence of the rate of silica weight loss on the gas flow rate normal to the interface, the rate of this reduction appears to be controlled by convective diffusion or mass transfer from the reacting surface.〔G. Han; H. Y. Sohn J. Am. Ceram. Soc. 88 () 882-888 (2005)〕〔R. A. Gardner J. Solid State Chem. 9, 336-344 (1974)〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「silicon monoxide」の詳細全文を読む スポンサード リンク
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