Melted condensed phosphates (CP) having high chemical activity, interact with oxoacid salts, halogenides, sulphides, oxides and nitrides as well as with metals, steels and alloys. Lithium and sodium sulphate destruct CP evolving O2 and SO2 into a gasous phase. In the reaction products di-, tri- and tetraphosphate solid and polymer anions have been revealed by paper-chromatography analysis. Increasing the temperature and the contact of sulphate, both the mean value of phosphate molecular mass and viscosity of metals decreased. Interacting with CP carbonates dissociated to form CO2. Lithium nitrate dissociated at 443 K, sodium and potassium nitrates at 593 and 663 K respectively. Potassium sulphate decreases the mean molecular mass (KPO3)n less than twofold, potassium nitrate does it more than 10 times under similar conditions. In the series Li6TeO6-Li2SO4-Li2CrO4 potassium chromate reacted actively with (LiPO3)n to form chromium (III) monophosphate, a valuable binding material and catalyst. Interacting with Cr2S3MnS, NiS, Cu2S4FeS, melted condensed phosphates stimulated the formation on sulphur, SO2 and P4. In solid melts metal phosphides have been found as well a mono-, di- and tetrapolyphos-phates. Condensed phosphate reactions with Mg3N2, A1N and TiN resulted in evolving PN, N2 and P4 into gaseous phase.