Thermal decomposition of thallium(I) perchlorate in presence of chromium(III) oxide
TL;DR: In this paper, the thermal decomposition of an intimate mixture of thallium(I) perchlorate and chromium(III) oxide revealed that chromium-III oxide lowers the decomposition temperature of the mixture and is oxidized into hexavalent state.
Abstract: Thermal decomposition of an intimate mixture of thallium(I) perchlorate and chromium(III) oxide revealed that chromium(III) oxide lowers the decomposition temperature of thallium(I) perchlorate and is oxidized into hexavalent state to give thallium(I) dichromate. The thermal decomposition was followed by constant temperature heating, thermogravimetry and differential thermal analysis. The reaction products were characterized by chemical analysis, X-ray diffraction and infrared spectral measurements.
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TL;DR: In this paper, the effects of three corundum structure oxides, α-Al 2 O 3, α-Cr 2O 3, and α-Fe 2 O3, on the thermal decomposition of sodium and potassium peroxodisulfates (persulfates) under non-isothermal static air conditions and using various oxide/persulfate molar ratios, have been thermoanalytically investigated.
Abstract: The effects of three corundum structure oxides, α-Al 2 O 3 , α-Cr 2 O 3 , and α-Fe 2 O 3 , on the thermal decomposition of sodium and potassium peroxodisulfates (persulfates) under non-isothermal static air conditions and using various oxide/persulfate molar ratios, have been thermoanalytically investigated Compounds such as Na 3 Al(SO 4 ) 3 , K 3 Al(SO 4 ) 3 , Cr 2 (SO 4 ) 3 , K 3 Cr(SO 4 3 , and Na 3 Fe(SO 4 ) 3 are identified by X-ray diffractometry and conventional chemical analysis The molar ratios as well as temperatures of the stoichiometric formation for these compounds have been established At higher temperatures, α-Al 2 O 3 acts as a promoter catalyst for the decomposition of pyrosulfate to sulfate, whereas α-Cr 2 O 3 behaves as a retarder for the decomposition of persulfate A eutectic mixture is formed between K 3 Al(SO 4 ) and K 2 SO 4 at 675°C Also, K 3 Fe(SO 4 ) 3 is identified as two crystalline phases
9 citations
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TL;DR: In this paper, the reaction between potassium iodate and molybdenum(VI) oxide in mixtures of different mole ratios has been investigated employing TG and DTA techniques in static air atmosphere.
Abstract: The reaction between potassium iodate and molybdenum(VI) oxide in mixtures of different mole ratios has been investigated employing TG and DTA techniques in static air atmosphere. The products are characterised by infrared spectroscopy, chemical analysis and X-ray diffraction studies. The studies indicate the formation of mono-, di-, tri- and tetramolybdates of potassium from mixtures with 2∶1, 1∶1, 2∶3 and 1∶2 mole ratios of KlO3∶MoO3. The kinetics of the reaction was followed and the energy of activation values were computed.
3 citations
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TL;DR: In this article, the thermal properties of chromium(III) perchlorate have been investigated using X-ray powder diffraction patterns and infrared spectral measurements, followed by TG and DTA techniques.
Abstract: Thermal behaviour of intimate mixtures of chromium(III) oxide and lithium1, potassium2, rubidium3, cesium3 and thallium(I)4 perchlorates revealed that chromium(III) oxide not only catalyses the decomposition by lowering the decomposition temperatures of the pure metal perchlorates but also chemically interacts resulting in the formation of metal dichromate. The oxidation of chromium(III) into the hexavalent state is attributed to the abstraction of oxygen from the perchlorate moiety during the decomposition. In this context, it was thought interesting to study the thermal behaviour of chromium(III) perchlorate and to identify the decomposition products in order to find out whether chromium(III) is oxidized into chromium(VI) by the perchlorate group. Except for a report5 on the preparation of chromium(III) perchlorate with different molecules of water of hydration no work seems to have been carried out on the thermal decomposition of this compound. In the present study, the decomposition characteristics are followed by TG and DTA techniques and the decomposition products have been examined by chemical analysis, X-ray powder diffraction patterns and infrared spectral measurements.
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TL;DR: In this article, the characteristic frequencies of 52 metals have been studied in the region 700-240 cm−1 and a particle size of 10 μ or smaller was found to give the best representative spectrum.
Abstract: The characteristic frequencies of oxides of 52 metals have been studied in the region 700-240 cm−1. Data for oxides of metals of different valence states and the frequencies of polymorphic forms of several oxides are presented. A particle size of 10 μ or smaller was found to give the best representative spectrum.
474 citations
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TL;DR: In this article, the influence of the oxides TiO2, V2O5, Co2O3, MnO2 and Tb4O7 on the thermal decomposition of lithium perchlorate trihydrate was surveyed.
Abstract: The influence of the oxides TiO2, V2O5, Co2O3, MnO2, Fe2O3, Co2O3, NiO, CuO, La2O3, CeO2, Pr6O11, Eu2O3, Gd2O3 and Tb4O7 on the thermal decomposition of lithium perchlorate trihydrate, was surveyed. Most of the oxides lowered the decomposition temperature of the anhydrous perchlorate; but their weight-loss matched the results obtained by heating lithium perchlorate without additives. Chromium(III) oxide and vanadium(V) oxide were exceptional.
8 citations
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TL;DR: In this paper, the reaction at 300°C between molten lithium perchlorate and chromium(III) oxide gave lithium dichromate, and a reaction mechanism was proposed.
Abstract: The reaction at 300°C between molten lithium perchlorate and chromium(III) oxide gave lithium dichromate. When lithium perchlorate and chromium(III) oxide were in the formula weight ratio of 2:1 respectively, the chromium was oxidized completely into the hexavalent oxidation state, and only a negligible chloride percentage of 0·1 remained in the resulting lithium dichromate.
Different formula weight ratios were taken for the reaction at 300°C. In the runs where the formula weight ratios of the perchlorate and oxide were lower than 2:1, the amount of chromium oxidized was higher than expected by the proposed route, and an explanation is given. Reactions with 51Cr2O3 showed that a very small amount of chromium volatilized.
Results obtained from experiments both in vacuum and air were in very good agreement. A reaction mechanism is proposed.
5 citations