The ranges of thermal stability and the temperature of explosion of all the [M(DMSO)6](ClO4)2 compounds (M = Cd, Mn, Zn, Ni, Fe, Mg and Sr) were determined and compared. This comparison showed that the most stable is a compound which contains Mn2+ ions and the least that which contains Sr2+ ions. Before reaching the temperature of the explosion some of the title compounds can release one or two DMSO molecules transforms into the corresponding four- and five-coordinate complexes. This process is reversible when the measurements are carried out for "closed" samples. The differential scanning calorimetry (DSC) measurements performed for [M(DMSO)6](ClO4)2 indicated its very rich and interesting phase polymorphism [1-3]. The crystallization by cooling of this compounds undergoes in a specific way because some of the phases can be very easily supercooled, and become the metastable phases. To facilitates the orientation in the polymorphism of [M(DMSO)6](ClO4)2, the schematic phase diagram for each of studied compounds has been created (see Fig 1). The values of molar enthalpy and entropy of the phase transitions, which can be read directly from the diagram, indicate that in high temperature range all studied compounds tend to create orientationally dynamically disordered crystals (ODIC) (called also as plastic crystals). On a basis of the results obtained for chosen [M(DMSO)6](ClO4)2 type compound, we will present the global analysis of the mechanism of detected phase transitions. This analysis would be based on a data obtained by infrared and Raman spectroscopy methods, solid state NMR spectroscopy, and structural analyses (X-Ray and neutron diffraction).