In an outer sphere electrochemical process, the plane of closest approach to the Outer Helmholtz Plane does not allow penetration of the layer of non-specifically adsorbed or coordinated solvent adhered to the electrode surface by reactants. In contrast, inner sphere electron transfer processes involve specifically adsorbed reactants, and therefore are anticipated to exhibit electrode kinetics that are strongly dependent on the chemical nature of the electrode surface. Thus, the [Fe(CN) 6 ] 3-/4-process can be designated as outer sphere under homogeneous chemical redox reaction conditions but inner sphere under electrochemical conditions at a glassy carbon electrode. Presumably, electron transfer at such electrodes is accompanied by interaction with surface functional groups, facilitated by the high negative charges associated with the [Fe(CN) 6 ] 3-reactant and [Fe(CN) 6 ] 4-product which allow specific binding or electrostatic attractive and repulsive interactions to accompany the electron transfer process. On this basis, the [Fe(CN) 6 ] 3-/4-electrode kinetics are strongly dependent on the treatment and origin of the glassy carbon.