The thermal dehydration and decomposition of M(IO3)2·2H2O (M2+=Ni2+ and Zn2+) and their deuterates were investigated by DTA and DSC methods. The data obtained confirm their onestage dehydration and
their decomposition to the respective oxides. Ni(IO3)2·2H2O and Ni(IO3)2·2D2O, were more stable than Zn(IO3)2·2H2O and Zn(IO3)2·2D2O. A considerable isotope effect was observed in relation toTdeh for Ni(IO3)2·2H2O and Ni(IO3)2·2D2O, which was explained by the presence of structural changes well differentiated from the dehydration process for the deuterate.
The data obtained for both pairs of dihydrates were used to determine ΔHfo
for Ni(IO3)2·2H2O and Ni(IO3)2·2D2O.
The thermal dehydration and decomposition of Cd(BF4)2·6H2O were studied by means of DTA, TG, DSC and X-ray diffraction methods and the end products of the thermal decomposition were identified. The results of thermal analysis show that the compound is fused first, then it is dehydrated until Cd(BF4)2·3H2O is obtained, which has not been described in the literature so far. The enthalpy of phase transition is δHph.tr.=115.6 kJ mol−1 Separation of the compound is difficult since it is highly hygroscopic. Then, dehydration and decomposition take place simultaneously until CdF2 is obtained which is proved by X-ray diffraction. On further increasing the temperature, CdF2 is oxidized to CdO and the characteristic curve assumes a linear character.
The thermal decompositions of two beryllium periodate hydrates, Be(IO4)2·8H2O and Be(H4IO6)2·2H2O, were studied by DTA and TG in the temperature range from 298 to 1073 K, and by DSC from 298 to 723 K. The intermediates of the thermal decompositions were identified via quantitative analysis, IR spectroscopy and the TG curves. The data obtained were utilized to suggest a scheme for the thermal decompositions of the two periodates. Both compounds decompose via an anhydrous beryllium iodate, and the final residue is beryllium oxide.
Barium peroxytitanate, Ba2[Ti2(O2)4(OH)4(H2O)4], was synthesized and its thermal decomposition in the temperature range from 298 to 1173 K was investigated. The intermediates at 423, 533, 773 and 873 K were identified by means of quantitative analysis, IR spectroscopy and X-ray diffraction analysis. On the basis of the data obtained, a scheme of its thermal decomposition was suggested.
Authors:M. Maneva, D. Rizova, L. Genov, and G. Liptay
The DTA method has been used in studying the thermal dehydration and decomposition of NiSO4.nH2O, accordingly of NiSO4.nD2O, (atn=7, 6, 4, 1) in a temperature interval of 20 to 900°C, at a heating rate of 10 deg/min. The endoeffects observed show in all cases partial dehydration to monohydrate and evolution of the last molecule of hydrate water at a high temperature Tmax ∼-360°C for the hydrates and Tmax ∼ 360-335°C for the deuterates. At NiSO4.6H2O (6D2O) and NiSO4.4D2O there occurs stepwise dehydration before the monohydrate as well. Decomposition of the anhydrous NiSO4 takes place at higher temperature which depends on whether it had been obtained from the respective deuterate ordinary hydrate. The one obtained from the deuterate undergoes decomposition at relatively lower temperature.
Authors:M. Subchev, T. Toshova, R. Andreev, V. Petrova, V. Maneva, T. Spasova, N. Marinova, P. Minkov, and D. Velchev
Field investigations with CSALOMON® floral-chemical baited color traps for scarab beetles (Coleoptera: Scarabaeidoidaea) were organized in eight sites in different regions in Bulgaria during 2009–2010. As a result data about distribution and seasonal flight were obtained for the target species Cetonia aurata L. and Protaetia cuprea (Fabricius) and two other non-target species, Valgus hemipterus L. and Blitopertha lineolata (Fischer von Waldheim). Catches of C. aurata were recorded in all of the sites where observations were organized but the number of the beetles caught was relatively low. The earliest catches of this pest were registered in the middle-end of April and the latest ones in early August. Single catches of P. cuprea, not allowing doing conclusions about seasonal flight for this species, were recorded only in Dryanovo, Knezha, Plovdiv and Troyan. Catches of V. hemipterus, were registered in all of the sites with the exception of Petrich. The flight period of this species, as established by catches in the traps, was middle-end of April — early June. Significant number of B. lineolata was caught in Dryanovo in 2009 and single catches in Plovdiv in 2009 and Kyustendil in 2009 and 2010. The earliest catches for the two years in Dryanovo were registered in the middle-end of May and the latest ones in the middle of June. This is the first report about floral-chemical attractant for this species. For all four species the relative catches in traps for C. aurata/P. cuprea, Tropinota (Epicometis) hirta (Poda) and Oxythyrea funesta (Poda), operating simultaneously in the investigated sites, were presented and analyzed.