Knowledge Bank

The microwave spectrum of $BH3NH3$ has been studied in the 30-125 GHz range. Five symmetric top isotopic species and two asymmetric rotor have been studied. The data allow a complete structural determination by the $ro$ method. The following structural parameters have been determined: B-N = 1.673 A, N-H = 1.008 A, B-H = 1.211 A, HNH = $108.8\circ ,HBH=114.0\circ .$ The internal rotation barrier is 2.03 kcal/mole. Analysis of the Stark effect of the 0-1 transition leads to = 5.216(17) Debye. A discussion of the pertinent structural parameters will be presented and a comparison of the internal rotation barriers with the isoelectronic species, ethane will be made.