Indium hexacyanoferrate (InHCF) thin films have:been successfully deposited on the SnO2-coated surface of conductive float glass by the sacrificial anode (SA) method. It was found that InHCF films prepared in such a way possess relatively smooth surface morphology, presumably influenced by the anodic dissolution current. The films have been characterized and discussed in terms of their electro-optical properties, The compositions of as-deposited InHCF films prepared by the SA method were analyzed by atomic absorption (AA) spectroscopy and can actually be expressed as H1-x(KxInFe(CN)(6). mH(2)O, with 0 less than or equal to x less than or equal to 0.38. Cyclic voltammetry (CV) done in various electrolytes supports the double injection/extraction mechanism during switching. It is concluded that ion permeability:in an InHCF film follows the order of Na+ > K+ > NH4+ > Li+. A one-electron transfer reaction is proposed for the switching of the InHCF film according to the absorption spectra. The film is shown to be electrochromic, and the redox reaction can be summarized asMInFeII(CN)(6). mH(2)) reversible arrow InFeIII(CN)(6). mH(2)O + M+ + e(-)where M+ is the metal cation in supporting electrolytes. The coloration efficiency for the InHCF film switching involving K+, measured at 410 nm, is 47.6 cm(2)/C for coloring and is 47.3 cm(2)/C for bleaching, indicating nearly ideal electrochromic behaviors.