Synthesis And Characterization Of New Hydrated Bismuth (Iii) Oxalates

This study presents results on the synthesis, crystal structure and thermal decomposition of three hydrated bismuth(III) oxalates. These compounds were obtained by precipitation from a Bi(NO3)(3) solution and oxalic acid under controlled pH and seem to correspond to Bi-2(C2O4)(3),7H(2)O, BiOH(C2O4) and Bi-2(C2O4)(3),6H(2)O formulae. They were characterized by FTIR, SEM, chemical analyses and XRD. Two of them present unknown XRD powder diagrams, which were resolved by TREOR analysis with an hexagonal (a = 9.9348 angstrom, c = 14.6386 angstrom) and an orthorhombic (a = 11.427 angstrom, b = 6.072 angstrom, c = 5.971 angstrom) cell, respectively. Their decomposition under air proceeds in several steps, which were analysed from TG-DTA experiments.