Empirical observations about angular geometries in the series B -HX

3 Empirical observations about angular geometries in the series B HX 

the axis of the HX molecule coincides with the supposed axis of a non-bonding electron pair as conventionally envisaged, or, if B has no non-bonding electron pairs but has -bonding electron pairs. 

HF lies along the extension of a median of the cyclopropane equilateral triangle 

the axis of the HX molecule intersects the internuclear axis of the atoms forming the 7r-bond and is perpendicular to the plane of symmetry of the 7t-bond. 

Rule (1) is definitive when B has both non-bonding and t-bonding pairs. 

---