THERMAL-DECOMPOSITION CHARACTERISTICS OF AMMONIUM HEXACHLOROMETALLATE(IV) COMPLEX SALTS OF PLATINUM METALS

The thermal decomposition behaviour of ammonium hexachlororuthenate(IV ), palladate(IV), osmate(IV), iridate(IV) and platinate(IV) was invest igated in nitrogen atmosphere using TG and DTA techniques. X-ray powde r diffractometry was used to identify the final solid decomposition pr oducts. The thermal decomposition of the complex salts yields the resp ective metals as the final residue. The thermal decomposition mechanis m of these complex salts is suggested and the thermal stability in the solid state is discussed in terms of inorganic energetics, such as th e ligand field stabilization energy and lattice energy. The sequence o f thermal stability of the complex salts was found to be Os(IV) > Ir(I V) > Pt(IV) > Ru(IV) > Pd(IV).