Silicon is the element most similar to carbon, however it is not a generic(属的) replacement for all carbon atoms and certain strict limitations apply. Double bonds to silicon, and three-membered rings containing silicon, are unstable to air and moisture Single bonds from silicon to heteroatoms such as nitrogen and oxygen are strong but can hydrolyze readily. 4.1.2 Differences between Silicon and Carbon Compounds
Silicon is the element most similar to carbon, however it is not a generic(属的) replacement for all carbon atoms and certain strict limitations apply. Double bonds to silicon, and three-membered rings containing silicon, are unstable to air and moisture Single bonds from silicon to heteroatoms such as nitrogen and oxygen are strong but can hydrolyze readily. 4.1.2 Differences between Silicon and Carbon Compounds
四川大学化学学院 2002年7月26日 12 The silicon-hydrogen bond is more polarized than the carbon-hydrogen bond. Polarization: Si－H > C－H In contrast to the carbon case, increasing the number of hydrogen on a silicon increases the ease of oxidation, and the parent silane (SiH4 ) is pyrophoric(发火的、生火的). Nevertheless, an analog of polyethylene that is rich in SiH2 groups has recently been reported to be air stable more Differences between Silicon and Carbon Compounds
四川大学化学学院 2002年7月26日 12 The silicon-hydrogen bond is more polarized than the carbon-hydrogen bond. Polarization: Si－H > C－H In contrast to the carbon case, increasing the number of hydrogen on a silicon increases the ease of oxidation, and the parent silane (SiH4 ) is pyrophoric(发火的、生火的). Nevertheless, an analog of polyethylene that is rich in SiH2 groups has recently been reported to be air stable more Differences between Silicon and Carbon Compounds
[SiH2－CH2－CH2－SiH2－CH2－SiH2－CH2 ]n Polyvinyl silane: Stable H2C=CH2 Ethylene: Stable H2Si=CH2 vinyl silane: unstable [CH2 CH2 CH2 CH2 CH2CH2 ] n Polyethylene: Stable
[SiH2－CH2－CH2－SiH2－CH2－SiH2－CH2 ]n Polyvinyl silane: Stable H2C=CH2 Ethylene: Stable H2Si=CH2 vinyl silane: unstable [CH2 CH2 CH2 CH2 CH2CH2 ] n Polyethylene: Stable
A subtle yet influential difference in atomic size exists for silicon and carbon , Important differences in chemical reactivity also exist. When silicon is proximal(最接近的) to unsaturation, as in a vinyl or allyl silane, the compounds are stable, but unlike their carbon analogs they are subject to acid catalyzed siliconcarbon bond cleavage Breaking of C－Si bond is easy Herein lies a potential avenue(方法) for the design of environmentally degradable products
A subtle yet influential difference in atomic size exists for silicon and carbon , Important differences in chemical reactivity also exist. When silicon is proximal(最接近的) to unsaturation, as in a vinyl or allyl silane, the compounds are stable, but unlike their carbon analogs they are subject to acid catalyzed siliconcarbon bond cleavage Breaking of C－Si bond is easy Herein lies a potential avenue(方法) for the design of environmentally degradable products
R Si H + R Si H2 O R H + HO Si
R Si H + R Si H2 O R H + HO Si