Catalytic oxide coatings for electrolytic chlorine production have traditionally been prepared by the thermal decomposition of a solution of suitable precursors. A variety of reports, however, have shown these coatings to exhibit spatial, chemical and morphological heterogeneity [1-4]. While this does not appear to detract from the performance of such coatings, a thorough understanding of the relative importance of crystallographic, morphological and chemical components requires that such heterogeneity is reduced to a minimum. Other, more controllable, approaches to the preparation of such coatings, e.g. sol-gel, have been reported [5-7], but either suffer from poor adhesion or require specialist equipment. Electrodeposition of single metal electrocatalytic films has been reported [8], but the use of electrodeposition to prepare the technologically interesting Ru-Sn system has not been described previously. The work reported here describes such an approach. Plating solutions were prepared using commercial RuC13 and SnC14 " 5 H 2 0 , dissolved in 1 moldm -3 sulphuric acid. Coatings were deposited onto 6 mm wide strips of titanium, previously etched in 10% oxalic acid (w/v) at 90 °C for 4 h. Deposition was performed galvanostatically, at room temperature, using a Pt mesh anode, surrounding the titanium cathode. Confirmation of deposition was achieved using X-ray fluorescence (XRF) and X-ray diffraction (XRD). A range of plating solution compositions at a constant current density of 30 mA c m -2, for 30 min, were used for deposits A-C. Deposit D was formed at the same current density, but with current reversal every 6rain for l h . The compositions of the resulting coatings were determined by XRF and are summarized in Table I.