Microwave Spectrum, Structure, Boron Quadrupole Coupling Constants, and Dipole Moment of Difluoroborane

The microwave spectra of H¹⁰BF₂, H¹¹BF₂, D¹⁰BF₂, and D¹¹BF₂ have been assigned. Rotational constants are 74 494.82, 10 496.74, and 9181.67 Mc/sec for H¹¹BF₂ 77 244.25, 10 495.35, and 9221.49 Mc/sec for H¹⁰BF₂ 52 896.09, 10 498.29, and 8740.46 Mc/sec for D¹¹BF₂ and 54 081.82, 10 496.89, and 8771.57 Mc/sec for D¹⁰BF₂. The structural parameters obtained from these constants and their estimated uncertainties are $r_{\mathrm{BH}}\text{\hspace{0.17em}=\hspace{0.17em}1.311\hspace{0.17em}±\hspace{0.17em}0.005 Å}$ , $r_{\mathrm{BH}}\text{\hspace{0.17em}=\hspace{0.17em}1.189\hspace{0.17em}±\hspace{0.17em}.010 Å}$ , and $\angle \mathrm{FBF}\text{\hspace{0.17em}=\hspace{0.17em}118.3°\hspace{0.17em}±\hspace{0.17em}1°}$ . The quadrupole coupling constants have been obtained. The dipole moment is 0.971 ± 0.010 D.