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The homogeneous gas-phase thermal decomposition kinetics of germane have been measured in a single-pulse shock tube between 950 and 1060 K at pressures around 4000 torr. The initial decomposition is GeH4 -GeH2 + H2 in its pressure-dependent regime, with log k~~~~( 4 m ) = 13.83 f 0.78 -50,750 f 3570 ca1/2.303RT. RRKM calculations suggest that the high-pressure Arrhenius parameters are log k GeH4(M -a) = 15.5 -54,300 cd2.303RT.Extrapolations to static system pyrolysis conditions (T -600 K, P -200 torr) give homogeneous reaction rates which are much slower than those observed, hence the static system pyrolysis of germane must be predominantly heterogeneous. Shock-initiated pyrolysis reaction stoichiometry is 2 mol H2 per mole GeH4, suggesting that the subsequent decomposition of germylene is essentially quantitative. Investigations of the hydrogen product yields for pyrolysis of GeD4 in @CH3 further indicate that the germylene decomposition reaction is mainly GeHz -H2 + Ge, hut that a small amount of reaction to H atoms may also occur.

The shock-initiated decomposition of tetramethylgermane (107%1242 K ) has been found to involve successive elimination of methyl radicals with the rate constant k l for the first step given by log k l (s-') = (17.00 f 0.35) -(77.0 f 1.9)/0 kcal/molIn the presence of excess toluene the products were CH4 (major), C2H4, and C2He. Results relevant to the reaction of methyl radicals with toluene compared to methyl radical recombination are discussed.

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