Silicon redistribution with

Errors in the low-density regions of the crystal were also found in a MaxEnt study on noise-free amplitudes for crystalline silicon by de Vries et al. [37]. Data were fitted exactly, by imposing an esd of 5 x 10 1 to the synthetic structure factor amplitudes. The authors demonstrated that artificial detail was created at the midpoint between the silicon atoms when all the electrons were redistributed with a uniform prior prejudice extension of the resolution from the experimental limit of 0.479 to 0.294 A could decrease the amount of spurious detail, but did not reproduce the value of the forbidden reflexion F(222), that had been left out of the data set fitted. 

Other more complex polymers have been employed as silicon carbide precursors. For instance, the mixture of methylchlorodisilanes obtained as a by-product in the direct synthesis of Me2SiCl2 can be redistributed with catalysts to give a polycyclic, partially cross-Uuked polymer with the approximate composition shown in equation (44). Pyrolysis of this precursor produces silicon carbide in good yield. Partially cross-linked polymers made by condensing vinylmethyldichlorosilane and other methylchlorosilanes with sodium also are efficient precursors for silicon carbide. 

It was shown that chromium disilicide (CrSi2, Eg= 0.35 eV) nanociystallites are embedded in monocrystalline lattice by reactive deposition epitaxy (RDE of Cr) and Si molecular beam epitaxy (MBE) [1]. Redistribution of CrSi2 NCs has been observed in silicon-silicide-silicon heterostructures with one embedded layer by HR XTEM data [2]. 

The redistribution reactions mentioned above indicate that the opening of a coordination site not only promotes oxidative addition and possibly a-bond metathesis reactions, but — difG ndy from carbon compounds — also induces migrations of silicon substituents with the concomitant formation of silylene complex intermediates. It was pointed out by Tilley and co-workers that the transfer of a silyl substituent from silicon to platinum is easier in three- than in four-coordinated... 

As stated earlier by Chojnowski and Cypryk [13], a functional disiloxane can also be introduced in the DCM, in addition to triflic add, to generate a,(o-telechelic PDMS for use in further grafting reactions, such as divinyltetramethyldisiloxane V2 [74] or tetramethyldisiloxane M [75]. Another team also functionalized polystyrene chains (prepared by radical polymerization) on both ends with pentameth-yldisUoxane groups to produce, through triflic add redistribution with D4, a triblock copolymer this technique was quoted by the authors to be easier than the conventional approach, which employs the sequential anionic polymerization of both monomers [76]. Another example worthy of mention here is that reported by Cai and Weber, who started with a tetrakis Si—H-functionalized precursor (tetrakis (dimethylsiloxy)silane) to generate silicone stars [77]. 

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