Date of Award


Degree Name

Master of Arts



First Advisor

Dr. R. H. Anderson

Second Advisor

Dr. J. M. Kanamueller

Access Setting

Masters Thesis-Open Access


The sublimation pressures of triphenyl aluminum and triphenyl boron have been determined from simultaneous measurements of the rate of mass effusion and torsional recoil. For triphenyl aluminum the measured vapor presures are expressed by the equations:

logio (Pk/P°) = (12.76 ± 1.25) - (8214 ± 572) (K/T)

logio (Pt/p °) = (12.83 ± 1.34) - (8206 ± 615) (K/T)

where Pk and Pt are the pressures measured by the Knudsen-effusion and torsional-recoil techniques, respectively, and p° = 101.325 kPa. For triphenyl boron the measured vapor pressures are expressed by the equations:

log10 (Pk/p°) = (9.39 ± 0.13) - (5274 ± 46) (K/T)

log10 (Pt/p°) = (10.00 ± 0.07) - (5489 ± 27) (K/T)

where the same notation applies. The standard molar enthalpies and entropies, of sublimation of triphenyl aluminum monomer: Al (C6H5)3(cr) → Al (C6H5)3 (g), and dissociation of the solid dimer: {Al(C6H5) 3}2(cr) →2Al(C6H5) 3(cr) are estimated. The standard molar heat of formation of gaseous triphenyl boron: △fH°m {B(C6H5 )3 , g, 363 K} and the mean molar bond-dissociation enthalpy (B-C6H5) are calculated.

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