AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The present paper deals with the microstructural parameters calculated from X-ray diffraction data, electrical and optical investigations, and scanning tunneling microscopy (STM) studies on ZnIn2S4 IIIa layer type CdIn2S4-xSex (1.75 ≤ x ≤ 2.75) quaternary chalcogenides. Microstructural parameters such as dislocation density, root-mean-square strain, stacking fault probability, crystallite size anisotropy, and layer disorder parameters of these compounds have been calculated. The temperature variation of electrical conductivity (25−400 °C) confirmed semiconducting behavior. The band gaps of all these compounds obtained from STM and optical measurements are in the range 1.57−1.77 eV and are comparable to each other irrespective of the technique used.

Abstract The title systems have been investigated on samples quenched at 700, 800 and 1000 °C. Five new compounds have been obtained and characterized by X-ray powder diffraction: Spinel type MgGa0.2Cr1.8S4, two compounds crystallizing in the olivine structure, MgGaCrS4 and MgGaInS4, and two layered materials, MgGa1.5Cr0.5S4 and MgGa1.5In0.5S4. Lattice para­ meters and phase widths of the compounds are given.

The title systems have been investigated on samples quenched at 700, 800 and 1000 degrees C. Five new compounds have been obtained and characterized by X-ray powder diffraction: Spinel type MgGa0.2Cr1.8S4, two compounds crystallizing in the olivine structure; MgGaCrS4 and MgGaInS4, and two layered materials, MgGa1.5Cr0.5S4 and MgGa1.5In0.5S4. Lattice parameters and phase widths of the compounds are given.

Abstract The mixed valence compound Ga1.93V0.97S4 has been prepared and characterized by X-ray powder methods. The compound crystallizes in an α-FeGa2S4 structure. The lattice parameters of the hexagonal cell are a = 363.6 and c = 1207.1 pm. The structure has been refined by Rietveld methods.

The mixed valence compound Ga1.93V0.97S4 has been prepared and characterized by X-ray powder methods. The compound crystallizes in an alpha-FeGa2S4 structure. The lattice parameters of the hexagonal cell are a = 363.6 and c = 1207.1 pm. The structure has been refined by Rietveld methods.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

In the quasibinary system MnIn2S4-MnIn2Se4 a series of solid solutions of general formula MnIn2SxSe4-x exists for 2.4 ≥ x ≥ 0.2 with the layered MgAl2S4 structure. The samples have been characterized by X-ray powder diffraction and investigated by electrical measurements and diffuse reflectance spectroscopy. The compounds are semiconductors with optical band gaps varying between 1.6 and 1.2 eV depending on x. From Arrhenius plots of the conductivity data at least two different activation energies Ea can be obtained: in the temperature interval from 50 to 200°C we find Ea = 0.5 eV, independent of the composition of the samples, while in the high temperature region from 200 to 400°C, Ea varies with x from 1.35 to 0.56 eV.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The mixed valence compound Ga0,5V2Se4 has been prepared and characterized by X-ray powder methods and infrared spectroscopy. The compound crystallizes in a spinel structure with 1:1 ordering on the tetrahedral sites. The lattice parameter of the cubic cell is a = 1013.8 pm.

The systems MnGa2S4MnV2S4, MnGa2S4MnTi2S4 and the corresponding magnesium systems MgGa2S4MgV2S4 and MgGa2S4MgTi2S4 were studied by x-ray diffraction methods on quenched powder samples. In all four systems new quaternary compounds crystallizing in a layered structure have been obtained. MgGa1.6Ti0.4S4 (a = 370.9, c = 1219.1 pm) adopts a structure of α-FeGa2S4-type while MnGa1.6Ti0.4S4 (a = 370.9, c = 1219.0 pm) and MnGa1.8V0.2S4 (a = 370.2, c = 3652 pm) are of ZnIn2S4(IIIa)-type at 700 °C and undergo a phase transition to the α-FeGa2S4 type at 960 °C. Samples of MgGa1.6V0.4S4 consist of a mixture of both layered structures.

The systems CoGa2S4CoV2S4 and CoGa2S4CoTi2S4 were studied by x-ray diffraction methods on quenched powder samples. In both systems new quaternary compounds CoGa1.8V0.2S4 and CoGa1.8Ti0.2S4 crystallizing in the trigonal layered structure of FeGa2S4 type (a=364.5, c=1203.8 pm and a=364.3, c=1205.8 pm, respectively.) have been obtained. They are formed only at temperatures above 800 and 900 °C, respectively, but can be quenched without decomposition. The phase width of both compounds increases with increasing temperature. For the end member compounds no phase width could be detected.

The crystal structure of CoGaInS4 has been determined from single crystal X-ray diffraction data and refined to R = 0.03. It crystallizes in the trigonal FeGa2S4 type (space group P3m1, No. 164, a = 3.759(1), c = 12.184(2) Å, Z = 1) with the following cation distribution: (Co0.61In0.39Ga)t(Co0.39In0.61)oS4. The system xCoGa2S4-(1 − x)CoIn2S4 is quasibinary. The compound CoGaInS4 has a large region of homogeneity with a marked dependence on temperature, ranging from x = 0.2 to x = 0.8 at 800°C. Compounds with high indium content show a phase transition to the ZnIn2S4(IIIa) type at 1000°C. Electronic spectra have been recorded on samples with different composition and on samples quenched from different temperatures.