Molecular Energetics of Borane Carbonyl and the Symmetric Dissociation Energy of Diborane

摘要

Large concentrations of borane, BH3, are produced upon the pyrolysis of borane carbonyl. Ionization efficiency measurements using a fast inlet masshyphen;spectrometric technique, have led toI(BH3) as well asA(Bplus;),A(BHplus;),A(BH2plus;), andA(BH3plus;) from BH3CO. These numbers permit a complete development of the molecular energetics of BH3CO and a confirmation of the symmetric dissociation energy of diborane of 59 kcal/mole. Earlier equilibrium data on the BH3CO decomposition, combined with these electronhyphen;impact data, also confirmDlpar;BH3sngbnd;BH3rpar;thinsp;equals;thinsp;59kcalsol;mole. Earlier kinetic studies that suggest a very much lower dissociation energy are shown to be equivocal at best.