Charge Fluctuation in Quasi-One-Dimensional Halogen-Bridged Platinum Binuclear Mixed-Valence Compounds, A4[Pt2(pop)4I]·nH2O

Abstract New quasi-one-dimensional halogen-bridged platinum binuclear mixed-valence compounds, A4[Pt2(pop)4I]·nH2O (A=alkaline metal and NH4, and; n=0, 2 and 4) have been synthesized. The Li, Na and K compounds take structures -Pt2.5+-Pt2.5+-X-Pt2.5+-Pt2.5+-X- (a). On the other hand, the Cs and Rb compounds take structures …Pt2+-Pt2+…X-Pt3+-Pt3+-X… (b). Interestingly, the NH4 compound takes a phase transition between (a) and (b) around 200K.