(2)
The bond-axiality Aσ quantifies the resultant BCPmotion along the bond-path, that coincides with thee direction, that we refer to as the bond-axial direction. The bond-axiality Aσ provides a measure of symmetry breaking 35 in response to the bond torsion directions (CCW vs. CW). The bond-axiality Aσ is defined as:
Aσ = [(e∙dr)max ]CCW- [(e∙dr)max ]CW