Infrared spectrophotometric determination of hydrogen-containing impurities in silicon tetrachloride

Theoretical Study of the Reaction Mechanism and Role of Water Clusters in the Gas-Phase Hydrolysis of SiCl4

“…As can be seen from the data, the most stable compound is trichlorosilanol SiCl 3 OH and that species should prevail in an equilibrium mixture. This conclusion is in agreement with experimental data from the infrared spectroscopy of impurities in liquid SiCl 4 at room temperature . As mentioned above, it was shown in this study that the OH-containing impurities are slowly converted into siloxanes in a 1:1 ratio by reaction 4b, confirming that the most stable OH-containing species under water deficient conditions is SiCl 3 OH.…”

“…This conclusion is in agreement with experimental data from the infrared spectroscopy of impurities in liquid SiCl 4 at room temperature. 8 As mentioned above, it was shown in this study that the OH-containing impurities are slowly converted into siloxanes in a 1:1 ratio by reaction 4b, confirming that the most stable OH-containing species under water deficient conditions is SiCl 3 OH. Table 4 shows the calculated energies and thermodynamic parameters of the condensation reactions for the hydrolysis of SiCl 4 .…”

“…Although this complex was not characterized by physical methods, its presence was required to describe all of the features observed in the experiment. Later, direct infrared spectroscopic analysis of impurities in liquid SiCl 4 was performed 8 and it was concluded that one of the major impurities of SiCl 4 (apart from HCl and siloxane SiCl 3 -O-SiCl 3 ) were the OH-containing species. Contrary to the proposal that the condensation step is very rapid, the infrared absorptions of the OH groups were very stable and disappeared only after boiling the reaction mixture for 4 h. Simultaneously, the concentration of siloxanes increased in a 1:1 ratio relative to the concentration of the OH derivatives.…”

Quantum-chemical calculation of the thermodynamics of multistep hydrolysis of MX4 molecules (M = C, Si, Ge; X = H, F, Cl) in the gas phase

“…This problem calls for further study. The formation of the products of reactions (3) and (4) was experimentally observed for SiCl 4 and GeCl 4 in an inert solvent and in molten chlorides [18][19][20][21][22] and for SiF 4 and GeF 4 in the gas phase [23,24]. For SiF 4 , the calculated ∆ r G 0 (298) values of reactions (3) and (4) are in good agreement with the experimentally determined values.…”

Theoretical Study of the Reaction Mechanism and Role of Water Clusters in the Gas‐Phase Hydrolysis of SiCl4.

“…Although this complex was not characterized by physical methods, its presence was required to describe all of the features observed in the experiment. Later, direct infrared spectroscopic analysis of impurities in liquid SiCl 4 was performed 8 and it was concluded that one of the major impurities of SiCl 4 (apart from HCl and siloxane SiCl 3 -OSiCl 3 ) were the OH-containing species. Contrary to the proposal that the condensation step is very rapid, the infrared absorptions of the OH groups were very stable and disappeared only after boiling the reaction mixture for 4 h. Simultaneously, the concentration of siloxanes increased in a 1:1 ratio relative to the concentration of the OH derivatives.…”