Thermal decomposition of some divalent metal selenates

Thermogravimetry, differential thermal analysis and differential thermogravimetry have been used to study the decomposition of hydrated selenates of manganese(II), cobalt, nickel, copper(II), zinc and cadmium. Based on the results obtained, mechanisms of decomposition have been proposed. The decomposition temperatures of non-hydrates show a gradual increase from manganese(II) selenate to zinc selenate and then a sudden drop for cadmium selenate.     

Studies on double malonates. III. Thermal decomposition of sodium lanthanide malonates,Na5Ln(C3H2O4)4.7.5H2O,where Ln=Gd,Tb or Ho

The double malonates of gadolinium, terbium and holmium with sodium, of the type Na₅Ln(C₃H₂O₄)₄.7.5H₂O, have been studied by means of thermal analysis. A mechanism of thermal dehydration and decomposition has been proposed on the basis of the results obtained.

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Zusammenfassung Doppelmalonate von Gadolinium, Terbium und Holmium mit Natrium des Typs Na₅Ln(C₃H₂O₄)₄.7,5 H₂O wurden mittels thermischer Analyse untersucht. Für die thermische Dehydratisierung und Zersetzung wird ein auf den erhaltenen Ergebnissen basierender Mechanismus vorgeschlagen.

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, Na₅Ln(C₃H₂O₄)₄.7.5H₂O. .

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Part II. Communicated     

Zinc Hydrogen Ortho Arsenate Trihydrate,ZnHAsO4 · 3 H2O

Zinc hydrogen ortho arsenate trihydrate, ZnHAsO₄ · 3 H₂O has been studied by static isothermal dehydration, X-ray powder diffraction, and infra-red absorption spectral techniques. The results of these studies clearly indicate that the compound is to be formulated as zinc hydroxide dihydrogen ortho arsenate dihydrate, Zn(OH)(H₂ASO₄) · 2 H₂O.     

Copper Hydrogen Orthoarsenate Monohydrate,CuHAsO4 · H2O isothermal decomposition and X-Ray diffractometric studies

Thermal decomposition of copper hydrogen orthoarsenate monohydrate has been studied by isothermal technique and X-ray diffraction method. The decomposition to the final diarsenate proceeds through the formation of an intermediate anhydrous salt. The lattice parameters for the starting monohydrate and the two dehydrated-decomposed compounds have been evaluated.     

Synthesis and crystal chemistry of triple orthoarsenates,CaLnTh(AsO4)3

A series of triple orthoarsenates CaLnTh(AsO₄)₃, where Ln=lanthanide or yttrium, are synthesized and spectrostructurally studied to evaluate the effect of rare earth ionic contraction on the crystal habitat of this class of arsenates. The results are analyzed and interpreted in comparison with the isostructural arsenates.