Infrared spectra of a series of anhydrous (Rb, Cs) and hydrated (Na, K, Ca, Sr, Ba, Pb, Ag, Tl) salts of the complex anion VO(C3H2O4)2]2− were recorded and briefly discussed. The thermal behaviour of these compounds, as well as that of the corresponding diprotonated ethylenediamine cation, were investigated by TG- and DTA-methods in N2-atmosphere and complemented with studies carried out in crucible furnaces in air. Pyrolysis intermediates and residues were characterized by IR spectroscopy and overall stoichiometries for the degradation processes were proposed. In most cases orthovanadate/VO2 mixtures were obtained as final residues in N2, whereas the corresponding divanadates were produced in air.
The electronic (absorption and reflectance) as well as the infrared and Raman spectra of Na6[(VO)3(P2O7)3]·7H2O were recorded and discussed. Its thermal behavior was investigated by means of TG and DTA measurements. After a two-step dehydration, the compound melts at 464°C and, apparently, depolymerization takes place during this process. The characteristics of the pyrolysis residues, collected at different temperatures, were spectroscopically investigated.
The thermal behaviour of a series of oxovanadium(IV) complexes of halogenated derivatives of 8-hydroxyquinoline was investigated by means of TG and DTA measurements in oxygen atmosphere. V2O5 was the final pyrolysis residue in all cases.
The thermal behaviour of SnP2O7 and PbP2O7 were investigated. The tin compound is stable at least at temperatures up to 1150°, whereas PbP2O7 begins to loss oxygen around 400°. The spectroscopic and roentgenographic analysis of the decomposition product, shows that it is the known polymeric lead(II) metaphosphate.
Authors:R. Mercader, E. Baran, and A. López-García
The Mössbauer parameters of anhydrous monoclinic tin/II/ phosphate, Sn3/PO4/2, are reported and briefly discussed. The results agree with the interactions expected from the crystalline structure but differ from previously reported data.
Authors:S. Tarulli, O. Quinzani, J. Dristas, and E. Baran
Complexes of Cu(II) with substituted o-acetoxy benzoic acids (5-haloaspirines, X-asp) with and without pyridine (py), of composition
[Cu2(X-asp)4] and [Cu(X-asp)2(py)2 ] have been synthesized and characterized. Electronic and vibrational spectroscopic data of these complexes are reported.
Its thermal behaviour was investigated by thermogravimetry and differential thermal analysis. In all complexes, the haloaspirinate
ligands decompose in two or three steps, starting with the break up of the coordinated acetoxy groups. CuO is obtained as
the final pyrolysis residue in all cases.