I. Raman Spectra of Some Silicon Compounds. II. Kinetics of Oxidized Silver Solutions

I. Raman Spectra of Some Silicon Compounds. SiH4 : Two lines were observed in the gas and liquid. With the help of infra-red data a complete assignments made for the vibrational spectrum of silane. Si2H6(g) and Si2Cl6(l) : Three lines were observed in Si2H6(g) and some fourteen in Si2Cl6(l). Polarization measurements on the stronger lines of Si2Cl6 were made by a convenient method which is described. From a consideration of the relations among the modes of vibration of similar molecules having different symmetry, the analysis of the observed lines is facilitated by a knowledge of the assignments of the fundamental frequencies of SiH4, HSiCl3, and BrSiCl3. A definite assignment is made for the three observed lines Si2H6 is made and some evidence is presented for the existence of internal rotation in this molecule at room temperature. II. Kinetics of Oxidized Silver Solutions. The behavior of a number of reducing agents toward nitric acid solutions of agentic silver and of ozone has been observed. Argentic solutions may be reduced quantitatively by titration with any of a number of reducing agents using the disappearance of the argentic color as end point. The rate of oxidation by ozone of nitric acid solutions of silver nitrate and the rate of decomposition of these oxidized solutions has been studied using suitable technique and method of analysis. The reduction rate is found to fit the differential equation - d(Ag++)2/dt = k2 d(Ag++)2/(Ag+) + k4 (Ag++)4/(Ag+) (4) indicating simultaneous occurrence of two slow reactions. (The oxidized silver is assumed to be principally in the divalent state.) The oxidation rate is found to fit the equation d(Ag++)/dt = ko (Ag+)(O3) - reduction rate (10) The steady state reached on prolonged oxidation by ozone of nitric acid solutions of silver nitrate is shown to correspond approximately to the point where d(Ag++)/dt = 0 in equation 10 with the reduction rate given by equation 4. Equilibrium between three valence states of silver is postulated, probably according to the equation AgO+ + Ag+ + 2 H+ = 2 Ag++ + H2O. (2) The oxidation mechanism is probably AgO+ + H2O = Ag++ H2O2 combined with equation 2. The fourth order reduction reaction may be H2O + 2 Ag++ + AgO+ = 3 Ag+ + O2 + 2 H+.