PREPARATION AND THERMAL-DECOMPOSITION OF VARIOUS FORMS OF STRONTIUM OXALATE

Strontium oxalate exists in two different forms: the neutral strontium oxalate hydrate, SrC2O4 . H2O, and the acid salt of strontium oxalate , SrC2O4 . yH(2)C(2)O(4) . xH(2)O. Depending on the concentration of o xalic acid and ammonium oxalate as precipitating agents, both forms ca n be obtained. At a sufficiently low pH, the stoichiometric compound S rC(2)O(4)1/2H(2)C(2)O(4) . H2O is formed. The thermal decomposition of the different strontium oxalates is studied in different atmospheres using DSC, and TGA coupled with FTIR and MS. The TGA-EGA spectra indic ate that the anhydrous acid oxalate decomposes with the release of H2O , CO, CO2 and formic acid.