In the context of g values, how is the term axial defined?

In the context of g values, the term axial refers to a specific scenario in which two g values are the same while the third one is different. This situation commonly arises in the case of certain coordinate complexes, particularly those with an elongated or compressed geometry, such as octahedral complexes that may exhibit asymmetry in electronic distribution along specific axes.

The axial orientation typically pertains to the alignment of the magnetic field relative to the ligands surrounding the central metal ion. For instance, in a distorted octahedral complex, the g values along the axial axis (the axis pointing directly at the ligands) might be equivalent due to the symmetry of the ligand field interaction, while the equatorial plane brings about a different g value due to different ligand interactions.

This results in two g values being the same (the axial ones), representing the same interaction environment, while the third value reflects a different electronic transition due to the variations in ligand influence around the equatorial plane. Thus, the correct characterization of axial g values is indeed that two values are the same, while the strategic differences of the axial versus equatorial configurations in ligand placements influence the magnetic properties being observed.