  We derive a connection between the intrinsic tribological properties and the
electronic properties of a solid interface. In particular, we show that the
adhesion and frictional forces are dictated by the electronic charge
redistribution occurring due to the relative displacements of the two surfaces
in contact. We define a figure of merit to quantify such charge redistribution
and show that simple functional relations hold for a wide series of
interactions including metallic, covalent and physical bonds. This suggests
unconventional ways of measuring friction by recording the evolution of the
interfacial electronic charge during sliding. Finally, we explain that the key
mechanism to reduce adhesive friction is to inhibit the charge flow at the
interface and provide examples of this mechanism in common lubricant additives.
