Kinetics of the gas-phase reaction between iodine and monogermane and the bond dissociation energy D(H3GeH)

✍ Scribed by Paul N. Noble; Robin Walsh

• Publisher: John Wiley and Sons
• Year: 1983
• Tongue: English
• Weight: 623 KB
• Volume: 15
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.550150605

✦ Synopsis

The title reaction has been investigated in the temperature range of 403-446 K. Monoiodogermane and di-iodogermane together with hydrogen iodide were the main products, although a t high conversions a t least one other product was formed. GeHsI is clearly the primary product. Initial rates were found to obey the rate law

over a wide range of initial iodine and monogermane pressures. Secondary reactions (of GeHsI with 12) affect the subsequent kinetics, although a t sufficiently high initial reactant ratios ([GeH4]o/(Iz]o 2 100) an integrated rate equation fits the data with the same rate constants as the initial rate expression.

The observed kinetics are consistent with an iodine atom abstraction chain mechanism, and for the step 1 I t GeH4 d G e H 3 t HI log k l (dm3/mol.s) = (11.03 f 0.13) -(52.3 f 1.0 kJ/mol)/RTIn 10 has been deduced. From this the bond dissociation energy D(GeH3-H) = 346 f 10 kJ/mol(82.5 kcal/mol) is obtained. The significance of this value, together with derived values for Ge-Ge and Ge-C bond strengths, is discussed.