E. Elshereafy

Electrical conductivity properties of some O-substituted arylazo — Barbiturate complexes at different temperatures

Electrical conductivity properties of someo-substituted arylazo-barbiturate complexes at different temperatures are studied. The σo, ΔE andEg values are determined. The copper complexes derived from −H, −CH3 and −OCH3 substituted organic compounds are with semiconducting properties at low temperatures and insulator at high temperatures. All the carboxy and the cobalt and the the nitro complexes, and nickel-methyl complexes are of semiconducting behaviour. The data are explained in the light of extrensic and lattice vibrations and the width of the forbidden energy gap properties.ZusammenfassungBei verschiedenen Temperaturen wurden die elektrischen Leitfähigkeitseigenschaften einiger o-substituierter Arylazobarbiturat-Komplexe untersucht und Werte für σo,ΔE undEg ermittelt. Die durch H-, CH3- und OCH3-Substitution der organischen Verbindungen erhaltenen Kupferkomplexe zeigen bei niedrigen Temperaturen Halbleiter- und bei hohen Temperaturen Isolatoreigenschaften. Alle Carboxy- und Nitrokomplexe sowie die Kobalt- und die Nickel-Methyl-Komplexe zeigen Halbleiterverhalten. Die Ergebnisse werden angesichts von Störstellen- und Gitterschwingungen und der Breite der verbotenen Energiezone erklärt.

Mechanism of thermal decomposition and γ-pyrolysis of aluminum nitrate nonahydrate [Al(NO3)3·9H2O]

Thermal decomposition and γ-pyrolysis of aluminum nitrate nonahydrate have been investigated by means of X-ray, IR, UV/VIS, TGA and DTA. All the experimental results obtained before and after γ-ray irradiation elucidated the decomposition mechanism.

Electrical and thermal studies on copper complexes of phthalocyanine and biphthalocyanine and their derivatives

Abstract The electrical and thermal behaviour of metal-free biphthalocyanine and its Cu complex, and of phthalocyanine Cu complex were examined. The effect of chloro and carboxylic substitution was evaluated. The compounds show semiconductivity in the range 278–573 K. The activation energy for conduction was calculated and a conduction mechanism was proposed. The activation energy of the α → β phase transformation for some compounds was calculated using DTA. Decarboxylation was observed in both d.c. electrical conductivity and DTA measurements.

Thermal and electrical behaviour of nickel(II) and copper(II) complexes of 4-acetylamino-2-hydroxy-5-methylazobenzene

The thermal behaviour of the entitled nickel(II) and copper(II) complexes of ¯4-acetylamino-2-hydroxy-5-methyl azobenzene has been studied by means of differential thermal analysis (DTA), thermogravimetry (TG), X-ray powder diffraction, IR and electrical conductivity. A light has been thrown on the nature of interaction of the solvents of crystallization with the host complex. Some of the kinetic parameters are calculated and discussed.ZusammenfassungMittels DTA, TG, Röntgendiffraktionsuntersuchungen, IR und elektrischen Leitfähigkeitsmessungen wurde das thermische Verhalten der Titelverbindungen untersucht. Bei diesen ¯4-Acetylamino-2-hydroxy-5-methyl-azobenzolkomplexen von Nickel(II) und Kupfer(II) wurde auch die Natur der Wechselwirkung des Lösungsmittels der Kristallisierung mit der Komplexverbindung ergründet. Einige der kinetischen Parameter wurden berechnet und diskutiert.

Further investigations on the electrothermal properties of yttria-doped gallia ceramics

Abstract Numerous polycrystalline ceramic specimens of yttria-doped gallia, have been prepared in the solid state, have been studied by powder X-ray diffraction IR and UV spectroscopy. The electrical conductivities (D.C.) measured for various yttria contents and at various temperatures up to 150°C, and the bulk and true density, and the percentage porosity of the test samples are compared. Correlations of the results obtained have been determined. Some evidence of compound formation could be traced if prior firing had been carried out at 1350 °C, this was not the case when firing was carried out at 800°C. Doping gallia with yttria results in a decreased conductivity and an unaltered mode of conduction.

γ-Pyrolysis of crystalline sodium thiosulphate penta hydrate

Pure Na2S2O3·5H2O, was investigated carefully for its X-ray diffraction, IR-absorption spectra, UV/Vis-absorption spectra, thermogravimetric analysis, differential thermal analysis before and after various gamma ray absorbed doses. Results obtained were explained, compared and discussed in detail, leading to a mechanism for radiation damage in this system.

Electric studies on some metal biphthalocyanine complexes

Abstract Metal free biphthalocyanine and some of its metal complexes, namely (Mg, Ca, Sr; Zn, Cd and Sn, Pb) have been prepared by the well known urea fusion technique in the dry and solvent methods. The behavior of the prepared biphthalocyanine complexes as semiconductors has been investigated and studied within the temperature range which includes their structural phase transition. The conductivity of the tested samples increases three orders of magnitude on heating from room temperature up to 573 K. Zn and Cd biphthalocyanine complexes show signifi- cant change in slope (log σ vs. 1000/ T ) at lower temperatures with respect to the tested series of complexes. The activation energies for conduction are calculated in the lower and higher temperature regions. High temperature regions are characterized by higher activation energies.

Thermal-conductimetric studies on some isonicotinoyl hydrazone derivatives and their metal complexes

Abstract The cobalt, nickel, zinc and copper complexes of the isonicotinoyl hydrazones derived from benzoylacetone (Bz), salicyaldehyde (Sal) and 2-hydroxynaphthaldehyde (Naph) derivatives were prepared. The solid materials were subjected to thermal analysis, and their d.c. electrical conductivities were measured at varying temperatures. The results of conductivity and thermal analyses were correlated. The activation energy for conduction was calculated and discussed with respect to likely conduction mechanisms.

Spectral properties and temperature-dependence of semiconductivity of various doped bismuth trioxide polycrystals

Several samples of Nb2O5-doped Bi2O3 and Y2O3-doped Bi2O3 were carefully prepared and sintered at 700° for 3 hours. Extensive measurements were carried out on these samples, including X-ray diffraction spectra, infrared absorption spectra and the temperature-dependence of the DC-electrical conductivity in the solid state. The results obtained were discussed, correlated and interpreted. Finally, the optimum compositions were established and recommended for doped-Bi2O3 in the electronics industry.ZusammenfassungEinige Proben von mit Nb2O5 und Y2O3 gedopten Bi2O3 wurden hergestellt und bei 700 °C 3 Stunden gesintert. Von den Proben wurden Röntgendiffraktogramme und IR-Absorptionsspektren aufgenommen und die Temperaturabhängigkeit der elektrischen Gleichstromleitfähigkeit im festen Zustand gemessen. Die erhaltenen Ergebnisse werden diskutiert, zueinander in Beziehung gesetzt und interpretiert. Optimale Zusammensetzungen werden ermittelt und für gedoptes Bi2O3 in der Elektronikindustrie empfohlen.РезюмеНесколько образцов Bi2O3, легированных Nb2O5 и Y2O3, были получены спек анием в течении 3 часов при тем пературе 700°. Полученны е образцы были исследованы мет одом рентгеновской и инфр акрасной спектроско пии, а также измерением температ урной зависимости электропроводности. Проведено обсуждени е полученных результатов и устано влены некоторые корреляции. Найдены о птимальные условия л егирования образцов окиси висму та, которые представлены в качес тве рекомендаций для электронной промышленности.

Structural studies on new copper(II) phenylhydrazoacetylacetone isonicotinoyl hydrazone complexes

SummaryCopper(II) phenylhydrazoacetylacetone isonicotinoyl hydrazone complexes were prepared at two different pHs and characterized by elemental analysis and various physical techniques. In neutral solutions monoligand complexes (1) and (2) were obtained, but the bisligand complex (3) was obtained from solution at pH 10. The ligand H2L behaved either as monobasic bidentate or dibasic tridentate towards cupric ions. Magnetic and spectral data suggest square planar structures for [CuL·H2O]·H2O but an octahedral structure for [Cu(HL)2·2H2O]·3H2O.