The study of homogeneous distribution coefficients in determining the transition temperatures of isomorphologically analogous
components and in predicting the existences of some new unstable compounds has been carried out in detail with special references
to vitriols of nickel, manganese, zinc, copper and magnesium. In the course of the investigation with NiSO4·7H2O as host and54Mn as guest, the transition temperature of orthorhombic NiSO4·7H2O was shown to be 26.5 °C, and with orthorhombic ZnSO4·7H2O and MgSO4·7H2O as host and copper sulphate as guest, the limits of existences of orthorhombic CuSO4·7H2O and newly predicted CuSO4·6H2O were found to be 13.5° to 44 °C and 44° to 51 °C, respectively. In addition, the transition temperatures of orthorhombic
MnSO4·7H2O (10 °C), stable NiSO4·7H2O (30.5±5 °C) and orthorhombic ZnSO4·7H2O (39 °C) were verified. The new method of approach is very simple, reproducible and easily adaptable.