Microwave spectrum,structure, quadrupole coupling constants and dipole moment of carbon monoxide-borane

The J = 0 → 1 and J = 1 → 2 transitions of thirteen isotopic species of carbon monoxide-borane (BH₃CO) have been measured. The heavy atom r₂ structural parameters have been calculated in several ways so as to minimize the effects of the small carbon coordinate. The structural parameters found are: d(B-C) = 1.534 ± 0.01 Å, d(C-O)= 1.135 ± 0.01 Å. d(B-H)= 1.221 ± 0.001 Å, ∠HBC = 103.79 ± 0.06°, and ∠HBH = 114.50 ± 0.15°. In addition, a complete r₀ structure has been calculated by least-squares fitting the moments of inertia of all the isotopic species. A dipole moment of 1.698 ± 0.02 D was determined.