A Reinvestigation of the Structures of Diborane and Ethane by Electron Diffraction

Abstract

The ethane-like model for diborane has been eliminated and the bridge model confirmed in an electron-diffraction reinvestigation of diborane and ethane which has led to the bond angle and bond distance valueso ∠H_(bond)-B-H_(bond) = 121.5 ± 7.5°, B-B = 1.770 ± 0.013 A7., B-H_(bond) = 1.187 ± 0.030 A7., and B-H_(bridge) = 1.334 ± 0.027 Å. for diborane, and ∠C-C-H = 110.5 ± 3.5°, C-H = 1.114 ± 0.027 Å., and C-C = 1.536 ± 0.016 Å. for ethane. A reasonable combination of the values for ethane with the spectroscopic moments of inertia gives ∠C-C-H = 110.4°, C-H = 1.110 Å., and C-C = 1.535 Å., in excellent agreement with the purely electron-diffraction results and considerably more precise.

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