It was earlier reported that [(OH₂)(terpy)Mn(μ-O)₂Mn(terpy)(OH₂)]³⁺ (terpy = 2,2′:6′,2″-terpyridine) (1) adsorbed on layer compounds catalyzes water oxidation to O₂ (J. Am. Chem. Soc., 2004, 126, 8084). The derivative with 4′-chloro-2,2′:6′,2″-terpyridine (Clterpy), [(OH₂)(Clterpy)Mn(μ-O)₂Mn(Clterpy)(OH₂)](NO₃)₃ (2(NO₃)₃) was synthesized and characterized by UV-visible absorption spectroscopic and magnetic susceptibility measurements. 2 is instable in aqueous solution at room temperature, but the stability of 2 in solution significantly increased at 5 °C. The reaction of a 2–mica adsorbate with Ce^IV in water produced a significant amount of O₂, although the reaction of 2 with Ce^IV in a homogenous solution did not. However, the maximum turnover number (TN = 0.52) of 2 on the mica adsorbate was less than unity, indicating the non-catalytic O₂ evolution by 2 on mica in contrast to the cooperative catalysis by 1 on mica with TN = 15. The kinetic analysis showed that O₂ evolution follows first order kinetics with respect to 2 adsorbed on mica, with the first-order rate constant given to be 6.8 × 10⁻⁵ s⁻¹. The first order kinetics can be explained by O₂ evolution involved in the unimolecular decomposition of 2 adsorbed on mica, which might be ascribed to the destabilized higher oxidation state of 2 due to the electron-withdrawing chloro-substitution.