The thermal behaviour of the MH2(IO3)3 (M=K, Rb and NH4) isomorphous compounds, as well as the IR and Raman spectra have been investigated as part of a study of the properties of solid protonic conductors. Detailed stoichiometries, sustained by TG, DTA, XRD and IR analysis, have been developed into the three phases. There were also evidences of the formation of the [I3O8]− polymeric phases. Their stabilities were associated to the different polarizing power of the H, K and Rb cations.
The thermal behaviour of SnP2O7 and PbP2O7 were investigated. The tin compound is stable at least at temperatures up to 1150°, whereas PbP2O7 begins to loss oxygen around 400°. The spectroscopic and roentgenographic analysis of the decomposition product, shows that it is the known polymeric lead(II) metaphosphate.