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Abstract  

We have studied the dehydration and the calcination under atmospheric pressure of cyclotriphosphate tetrahydrate of nickel and sodium, NiNa4(P3O9)2·6H2O, between 25 and 700°C by thermal analyses (TG, DTA) infrared spectrometry and X-ray diffraction. This study allows us the identification and the crystallographic characterization of a new phase, NiNa4(PO3)6, obtained between 350 and 450°C. NiNa4(PO3)6 crystallizes in the triclinic system, P–1, with the following unit cell parameters a=6.157(3) Å, b=6.820(6) Å, c=10.918(6) Å, =80.21(5)°, =97.80(9)°, =113.49(3)°, V=409.8 Å3, Z=1, M(19)=25 and F(19)=48 (0.0095; 42). The calcination of NiNa4(PO3)6, between 500 and 600°C, leads to a mixture of long-chain polyphosphates NiNa(PO3)3 and NaPO3. The kinetic characteristics of the dehydration of NiNa4(P3O9)2·6H2O were determined and discussed. The vibrational spectrum of the title compound, NiNa4(P3O9)2·6H2O, was interpreted in the domain of the stretching vibrations of the P3O9 rings, on the basis of its crystalline structure and in the light of the calculation of the normal IR frequencies of the P3O9 ring with D3h symmetry.

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] are the main among the described methods in technical literature. One of these methods is also thermal treatment. Asbestos minerals are naturally occurring hydrous silicates, so that they decompose to release water by heating at high

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Journal of Thermal Analysis and Calorimetry
Authors: Seied Mahdi Pourmortazavi, Mehdi Rahimi-Nasrabadi, Iraj Kohsari, and Seiedeh Somayyeh Hajimirsadeghi

decomposition [ 5 – 8 ]. Because such information is valuable for specifying the reaction pathways, the kinetic constants are required to define the burning or explosion process. However, obtaining these data under such conditions is so difficult [ 9 , 10

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Kinetic investigation on thermal decomposition of organophosphorous compounds

N,N-dimethyl-N′,N′-diphenylphosphorodihydrazidic and diphenyl amidophosphate

Journal of Thermal Analysis and Calorimetry
Authors: M. Sovizi and K. Anbaz

. 1 , are two relatively new synthesized organophosphorus compounds; and hence, acquiring information concerning these compounds in the solid-state, including their thermal stability and thermal decomposition, is necessary. This research was initiated

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Melting and thermal decompositions of solids

An appraisal of mechanistic interpretations of thermal processes in crystals

Journal of Thermal Analysis and Calorimetry
Author: Andrew K. Galwey

. Anal. Cal. , accepted. 5 Galwey , AK Brown , ME et al. 1999 Thermal Decomposition of Ionic Solids Elsevier Amsterdam . 6

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] reported that yttria, on reacting with NH 4 HF 2 , forms a compound NH 4 Y 2 F 7 ·NH 4 F, which decomposes in two stages, at 260 and 380 °C, to give NH 4 Y 2 F 7 and YF 3 . Patwe et al. [ 6 ] reported that the fluorination of yttrium oxide using ammonium

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Abstract

The Hodge–de Rham Theorem is introduced and discussed. This result has implications for the general study of several partial differential equations. Some propositions which have applications to the proof of this theorem are used to study some related results concerning a class of partial differential equation in a novel way.

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content and particle size on the thermal decomposition of NC were also individually studied [ 4 , 5 ]. The thermal decomposition can be investigated by many thermoanalytical methods such as thermogravimetry (TG), differential thermal analysis (DTA

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ZEMPLÉNI, A., In the max-semigroup of probability distributions over the plane there is no Khinchine-type decomposition theorem, Studia Sci. Math. Hungar. 30 (1995), 303-311. MR 96j :60020

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available techniques, the differential scanning calorimetry (DSC) proved to be one of the most efficient methods for both screening and fundamental analyses of exothermic chemical reactions. Many organic compounds can decompose releasing a large amount of

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