The title compound, Fc(2)(Ph)PS.I-2, has been prepared and characterised in both the solid state and solution. Single crystal X-ray crystallography reveals that the adduct adopts a molecular charge-transfer structure in the solid state. Mossbauer spectroscopy confirms the presence of low spin Fe2+ but also indicates the presence of ca. 24% of an Fe3+ species. The electrochemistry of Fc(2)(Ph)PS.I-2, Fc(2)(Ph)PS and Fc(2)(Ph)P has been studied using a combination of cyclic voltammetry and differential pulse voltammetry. The data for Fc(2)(Ph)PS.I-2, show two redox processes, consistent with the sequential oxidation of the ferrocenyl groups to ferrocenium species.