The adsorption energies of Fc on Au(111) and Ag(111) surfaces, as presented in Figure , reveal key insights into their adsorption behaviour. The specific adsorption energies for each structure are listed in Table . Across all configurations, the adsorption of Fc on Au( The ELF profiles of the top-layer Au(111) surface report that the surface atoms experience minimal changes in charge distribution at adsorption. However, the ELF maps of the Fc molecule at adsorption configurations display distinct differences. For example, in the E-Fc(⏊) Au(111) configuration, the bottom Cp ring of E-Fc which is closer to the Au(111) surface slightly reduces in size compared to the top Cp ring. The highly localized red regions shift outward from the centre of the Cp rings, reflecting the D5h symmetry of E-Fc. Similarly, the analogous vertical adsorption configuration of S-Fc(⏊)/Au(111), is also shown in Figure . This may result from the stronger interactions between the bottom Cp ring and the Au(111) surface, leading to differences between the two Cp rings. Interestingly, the symmetry of Fc, eclipsed (E) or staggered (S) was retained in the adsorption interaction with Au(111) surface. In the cases of vertical Fc adsorption, as seen in the VCDD maps in Figures and, both configurations E-Fc and S-Fc exhibit apparently different mechanisms from the flat configuration. The vertical E-Fc(⏊) and S-Fc(⏊) adsorption configurations are very similar so we take the E-Fc(⏊)/Au(111) as an example in the discussion. In the top Cp ring, the electron densities of the hydrogen atoms and the carbon atoms (2pz orbitals) of the Fc moiety at adsorption have a further net electron density reduction, whereas the carbon atoms (2px and 2py orbitals) of Fc exhibit small net gain in electron density. The centre Fe atom of Fc plays a very important role as studies indicated that ionisation of Fc leads to an electron loss on the centre Fe.