Silicon tetrachlorosilane

Chlorotrimethylsilane Silane, chlorotrimethyl- (8,9) (75-77>4) Tetrachlorosilane Silicon chloride (8) Silane, tetrachloro- (9) (10026-04-7) Methyllithium-lithium bromide complex Lithium, methyl- (8,9) (917-54-4)... 

X-ray crystallographic work on silicates has helped to explain the apparent complexity of the so-called silicic acids . Orthosilicic acid, H4Si04, can be made by the hydrolysis of tetrachlorosilane (silicon tetrachloride). 

Reduction/Reaction with Hydrogen. Tetraduorosilane reacts with hydrogen only above 2000°C. Tetrachlorosilane can be reduced by hydrogen at 1200°C. Tetraio do silane can be reduced to sihcon at 1000°C (165). Reduction of tetraduorosilane with potassium metal to sihcon was the first method used to prepare sihcon (see Silicon and silicon alloys). The reduction of sihcon tetrachloride by ziac metal led to the first semiconductor-grade sihcon (166,167). 

These systems may all be applied to the same compound. The name adopted is then a matter of choice or convenience. Thus, SiCl4 can be named silicon tetrachloride (binary), tetrachlorosilicon (coordination) and tetrachlorosilane (substitutive). No one name is better or more correct than any other. 

The silicon is then converted directly to tetrachlorosilane by the reaction... 

With both the Fu and the Denmark catalysts it can be assumed that catalysis is effected by formation of a highly electrophilic silicon cation D from tetrachlorosi-lane and the nucleophilic catalyst C, i.e. by attack of the pyridine N-oxide or of the phosphoramide O-atom on silicon, followed by ionization (Scheme 13.38). The latter cation can then activate the epoxide toward nucleophilic attack by the chloride ion. Exchange of the product silane for another molecule of tetrachlorosilane completes the catalytic cycle [75],... 

According to this mechanism (Scheme 7.19), the process is amenable to asymmetric modifications. Among a variety of silicon reagents that were examined, only tetrachlorosilane proved to be suitable for the asymmetric process, while the application of other chlorosilanes resulted in the formation of racemates. A... 

Moran et al. have also reported the preparation of hyperbranched ferrocenyl. S7-based polymers (Figure 8.1). The construction of ferrocenyl —silicon polymers 40 and 41 was effected by the reaction of dilithioferrocene-TMEDA with the tetrachlorosilane 35 (see Scheme 8.10) and the Pt-mediated hydrosilylation of l,l -divinylferrocene with tetrasilyl-hydride 38. The 3-dimensional motif exhibited by hyperbranched polymers 40 and 41 is analogous to that depicted by the ferrocenyl — silicon network structures 38,43 42 and 43 (Figure 8.2). 

Dichloro neutral bis-chelates of hexacoordinate silicon were obtained by two methods directly (35) by transsilylation of Af-dimethylamino-O-(trimethylsilyl)acylimidates (1) with tetrachlorosilane, or by rearrangement as described in the previous section (70). The presence of two chloro ligands was utilized for further substitution, to form hexacoordinate silicon tris-chelates, by reaction with bis(trimethylsilyl)-precursors 71 and 72, as shown in Eqs. (31) and (32). The products (73, 74, and 75), are hexacoordinate neutral silicon tris-chelates, and 75 is the first reported zwitterionic tris-chelate with three different chelate rings.73... 

The formation of 4c can be explained by the reaction in which 1 mol of each of the two reactants reacted simultaneously with an equivalent of elemental silicon. Besides 1,3-disilaalkanes 3c and 4c, 2c was obtained in small amounts along with trichlorosilane and tetrachlorosilane. Cadmium was a good promoter for the reaction as observed in the direct reaction of reactant lc above, while zinc was found to be an inhibitor for this particular reaction. Other (chloromethyl)silanes la.b.d were also applied for this reaction.27... 

The reaction of silicon with a gaseous mixture of ethylene and hydrogen chloride was carried out at temperatures ranging from 240 to 260 °C, after preheating a mixture of elemental silicon and copper(I) chloride in a helium stream at 450°C.82 Ethyldichlorosilane was formed along with trichlorosilane, dichlorosilane, and tetrachlorosilane (Eq. 20). 

The study of silicon halides began in the eady 1800s (1). Since then, essentially all of the monomeric silicon halides have been extensively studied and reported in the literature. These include mixed silicon halides and halohydrides. A large number of halogenated polysilanes have also been reported (1). Despite the extensive research in silicon halides, only two of these chemicals are produced on alaige industrial scale (excluding oiganohalosilanes). These are tetrachlorosilane [10026-04-7], SiCl and trichlorosilane [1025-78-2], HSiCl. ... 

Oxidation. Silicon halides are stable to oxygen at room temperature, but react at elevated temperatures to form, in the ( oxychlorosilanes. Tetrachlorosilane reacts at 950—970°C to form hexachlorodisiloxane (160,161). 

Reaction with Silicon. At elevated temperature (1000 0) tetrachlorosilane attacks pure crystalline silicon to form a mixture of higher chlorosilanes including Si2Cljj, Si Clg, and Si Cl Q. Under vacuum at lOOO C, silicon tetrafluoride reacts with siUcon to form difluorosilene (162), which, using a rapid thermal quench below —60°C, forms polydifluorosilane, a wax-like polymer. The polydifluorosilane reverts to siUcon and siUcon tetrafluoride at moderate temperature. 

---