Synthesis and thermal study of tris(ammonium) hexafluoro metallates(III) of some rare earths

1989 ◽  
Vol 67 (11) ◽  
pp. 1815-1818 ◽  
Author(s):  
S. J. Patwe ◽  
B. N. Wani ◽  
U. R. K. Rao ◽  
K. S. Venkateswarlu
Keyword(s):  
Thermal Analysis ◽  
Thermal Decomposition ◽  
Hydrogen Fluoride ◽  
Rare Earths ◽  
Room Temperature ◽  
Thermal Study ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ammonium Hydrogen ◽  
New Compounds

Fluorination of oxides of rare earths using ammonium hydrogen fluoride at room temperature gave new compounds [NH4]3MF6•nH2O, where M = Y, La, Nd, and Pr. In the case of cerium, [NH4]4CeF8 is formed. The course of thermal decomposition of all these compounds is studied by thermogravimetry/differential thermal analysis (TG/DTA) and X-ray powder diffraction (XRD). Keywords: hexafluoro metallates, rare earths, ammonium hydrogen fluoride, thermal decomposition, X-ray diffraction.

STRUCTURE AND MAGNETIC PROPERTIES OF MECHANICAL ALLOYED Mn-15at.%Al

2013 ◽  
Vol 12 (01) ◽  
pp. 1350006
Author(s):  
AHMED E. HANNORA ◽  
FARIED F. HANNA ◽  
LOTFY K. MAREI
Keyword(s):  
Thermal Analysis ◽  
Room Temperature ◽  
Average Crystallite Size ◽  
Al Alloy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Milled Sample ◽  
Powder Samples ◽  
Xrd Patterns ◽  
Method Analysis

Mechanical alloying (MA) method has been used to produce nanocrystallite Mn -15at.% Al alloy. X-ray diffraction (XRD) patterns for the as-milled elemental α- Mn and aluminum powder samples show a mixture of α + β- MnAl phases after 20 h of milling and changes to a dominant β- MnAl phase structure after 50 h. An average crystallite size of 40 nm was determined from Hall–Williamson method analysis after 5 h of milling. Moreover, the thermal analysis results using differential thermal analysis (DTA), suggested a possible phase transformation after 20 h of milling. Isothermal treatments are carried in the temperature range of 450°C to 1000°C. Room-temperature vibrating sample magnetometer (VSM) measurements of the hysteretic response revealed that the saturation magnetization Bs and coercivity Hc for 10 h ball milled sample are ~ 2.1 emu/g and ~ 92 Oe, respectively.

Characterization of Three 'Active' Rhodium(III) Hydroxides

1995 ◽  
Vol 48 (3) ◽  
pp. 557 ◽  
Author(s):  
SJ Crimp ◽  
L Spiccia
Keyword(s):  
Thermal Analysis ◽  
Thermal Decomposition ◽  
Infrared Spectroscopy ◽  
Ion Exchange ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
X Ray Diffraction ◽  
X Ray

Pure solutions of [ Rh (H2O)6]3+, dimer [Rh2(μ-OH)2(H2O)8]4+ and trimer [Rh3(μ-OH)4(H2O)10]5+ have been converted into their respective 'active' hydroxides by dropwise addition to an imidazole solution. These 'active' hydroxides have been analysed by a variety of techniques including rhodium determination, infrared spectroscopy, thermal analysis and powder X-ray diffraction. Purity determinations using ion-exchange chromatography showed that the three hydroxides consist primarily of the neutral forms of the starting aqua ion (>96%) with small amounts of species with higher nuclearity. Rhodium analysis and thermogravimetric measurements confirmed the composition of these hydroxides to be Rh (OH)3(H2O)3.H2O, Rh2(μ-OH)2(OH)4(H2O)4 and Rh3(μ-OH)4(OH)5(H2O)5.5H2O. A scheme for the thermal decomposition of each of the hydroxides has been proposed on the basis of the t.g . and d.t.a . data and the knowledge that the final product in each case is α-Rh2O3. Heating of the hydroxides in air resulted in oxidation of RhIII to RhIV (temperature 250-300°C) forming RhO2 which on further heating decomposed to α-Rh2O3 and dioxygen.

STUDY ON PHASE DIAGRAM OF BaO-Y2O3-CuO TERNARY SYSTEM

1987 ◽  
Vol 01 (02) ◽  
pp. 363-365 ◽  
Author(s):  
Guangcan Che ◽  
Jingkui Liang ◽  
Wei Chen ◽  
Sishen Xie ◽  
Yude Yu ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Phase Diagram ◽  
Ternary System ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
High Tc ◽  
X Ray ◽  
High Tc Superconductor

In Ba-R-Cu-O system (R=La, Y) , high Tc superconductor have been discovered (1–3). The room temperature section of the phase diagram in BaO-Y2O3-CuO system has been completed by means of X-ray diffraction, thermal analysis and superconducting measurements.

scholarly journals Thermal Annealing and Phase Transformation of Serpentine-Like Garnierite

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 188
Author(s):  
Arun Kumar ◽  
Michele Cassetta ◽  
Marco Giarola ◽  
Marco Zanatta ◽  
Monique Le Guen ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Raman Spectroscopy ◽  
Phase Transformation ◽  
Differential Thermal Analysis ◽  
Thermal Treatment ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Thermally Induced ◽  
X Ray ◽  
Micro Raman Spectroscopy

This study is focused on the vibrational and microstructural aspects of the thermally induced transformation of serpentine-like garnierite into quartz, forsterite, and enstatite occurring at about 620 °C. Powder specimens of garnierite were annealed in static air between room temperature and 1000 °C. The kinetic of the transformation was investigated by means of thermogravimetric and differential thermal analysis, and the final product was extensively characterized via micro-Raman spectroscopy and X-ray diffraction. Our study shows that serpentine-like garnierite consists of a mixture of different mineral species. Furthermore, these garnierites and their composition can provide details based on the mineralogy and the crystalline phases resulting from the thermal treatment.

A twofold interpenetrating three-dimensional CdIIcoordination framework: poly[[μ2-1,3-bis(2-methyl-1H-imidazol-1-yl)benzene](μ3-5-nitrobenzene-1,3-dicarboxylato)cadmium(II)]

2014 ◽  
Vol 70 (12) ◽  
pp. 1138-1142 ◽  
Author(s):  
Le Li ◽  
Jian-Qing Tao
Keyword(s):  
Thermal Analysis ◽  
Solid State ◽  
Ir Spectroscopy ◽  
Room Temperature ◽  
Three Dimensional ◽  
Pentagonal Bipyramid ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Coordination Framework

A twofold interpenetrating three-dimensional CdIIcoordination framework, [Cd(C8H3NO6)(C14H14N4)]n, has been prepared and characterized by IR spectroscopy, elemental analysis, thermal analysis and single-crystal X-ray diffraction. The asymmetric unit consists of a divalent CdIIatom, one 1,3-bis(2-methyl-1H-imidazol-1-yl)benzene (1,3-BMIB) ligand and one fully deprotonated 5-nitrobenzene-1,3-dicarboxylate (NO2-BDC2−) ligand. The coordination sphere of the CdIIatom consists of five O-donor atoms from three different NO2-BDC2−ligands and two imidazole N-donor atoms from two different 1,3-BMIB ligands, forming a distorted {CdN2O5} pentagonal bipyramid. The NO2-BDC ligand links three CdIIatomsviaa μ1-η1:η1chelating mode and a μ2-η2:η1bridging mode. The title compound is a twofold interpenetrating 3,5-connected network with the {42.65.83}{42.6} topology. In addition, the compound exhibits fluorescence emissions in the solid state at room temperature.

Photoluminescence and photocatalytic activity of a 3D framework based on 4,4′-bis(1,2,4-triazol-1-ylmethyl)biphenyl as a ligand for cadmium

2019 ◽  
Vol 74 (7-8) ◽  
pp. 553-558
Author(s):  
Chen Zhang ◽  
Ning-Ning Chen ◽  
Jian-Qing Tao
Keyword(s):  
Thermal Analysis ◽  
Photocatalytic Activity ◽  
Phthalic Acid ◽  
Room Temperature ◽  
Three Dimensional ◽  
High Photocatalytic Activity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Coordination Framework ◽  
3D Framework

AbstractA novel three-dimensional Cd(II) coordination framework, [Cd(PTA)(BTBP)0.5 · H2O]n (1) (BTBP =  4,4′-bis(1,2,4-triazol-1-ylmethyl)biphenyl; H2PTA = p-phthalic acid), has been prepared and characterized through IR spectroscopy, elemental and thermal analysis, and single-crystal X-ray diffraction. The complex is a 5-connected network with the {45 · 66} topology based on Cd-μ2-H2O-Cd chains. It exhibits strong fluorescent emission in the solid state at room temperature. Moreover, complex 1 shows high photocatalytic activity in the degradation of methylene blue under UV irradiation.

The silver–calcium phase diagram

1969 ◽  
Vol 47 (4) ◽  
pp. 611-614 ◽  
Author(s):  
W. A. Alexander ◽  
L. D. Calvert ◽  
A. Desaulniers ◽  
H. S. Dunsmore ◽  
D. F. Sargent
Keyword(s):  
Thermal Analysis ◽  
Phase Diagram ◽  
Composition Range ◽  
Liquidus Curve ◽  
X Ray Diffraction ◽  
X Ray ◽  
Novel Technique ◽  
New Compounds ◽  
First Time ◽  
Made In

The silver–calcium system has been reinvestigated over the whole composition range by thermal analysis, X-ray diffraction, and metallography. A novel technique has been used to prepare and examine these reactive alloys. In the course of this project four intermetallic compounds have been observed for the first time; while two others, viz., Ag2Ca and AgCa, which were reported before by others, have been confirmed. Three of the new compounds are: Ag8Ca3, Ag3Ca5, and AgCa3, while the fourth was not isolated or examined in detail. Two other compounds which were described in earlier work as Ag4Ca and Ag3Ca, have been found to be Ag9Ca2 and Ag7Ca2, respectively. Major modifications have been made in the liquidus curve and possible reactions in the solid state are indicated.

Preparation of Mullite Whiskers from Powder of Topaz Pure and Doped with Rare Earths

2014 ◽  
Vol 798-799 ◽  
pp. 189-194
Author(s):  
Renato Reis Monteiro ◽  
Antônio Claret Soares Sabioni
Keyword(s):  
Thermal Decomposition ◽  
Aspect Ratio ◽  
Rare Earths ◽  
Glassy Phase ◽  
Xrd Analysis ◽  
Molar Ratio ◽  
Vitreous Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mullite Whiskers

Mullite whiskers were obtained by thermal decomposition of powders of natural topaz, pure and doped with 3 and 5% in weight of La2O3 and Y2O3, at the temperatures of 1300 and 1400°C, for 1h, in air. Pure and doped mullite whiskers showed a molar ratio Al2O3: SiO2 close to 2:1, rich in alumina. The aspect ratio (AR) of whiskers varies with dopant concentrations and temperatures. The ARs for pure whiskers were 28 and 31.5, at the temperatures of 1300 and 1400°C, respectively, showing no glassy phase. For the doped whiskers, there were observed a reduction in the ARs, ranging from 14.13 to 16.10 (3 and 5% La2O3) and from 6.32 to 7.35 (3 and 5% Y2O3), for the temperatures of 1300 and 1400°C, respectively. The Y2O3 was not entirely incorporated, and part of it formed Y2Si2O7 and Y2O3-δ, with δ = 0.33 according to quantitative X-ray diffraction analysis (XRD analysis) with the presence of small amount of vitreous phase.

The Thermal Decomposition Characteristics of Sodium Pyroxenite Gangue in Baiyunebo Iron Ore

2014 ◽  
Vol 887-888 ◽  
pp. 939-946
Author(s):  
Guo Ping Luo ◽  
Sheng Li Wu ◽  
Xiao Long Nie ◽  
Yi Ci Wang ◽  
Yue Cong Wang
Keyword(s):  
Thermal Analysis ◽  
Thermal Decomposition ◽  
Iron Ore ◽  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wide Range ◽  
Physical And Chemical ◽  
And Chemical Properties

The changes of physical and chemical properties of sodium pyroxenite gangue such as decomposition and phase transformation were researched by means of differential thermal analysis and X-ray diffraction. The results show that the natural sodium pyroxenite gangue contains the main mineral of aegirite(NaFe+3Si2O6), and it contains a number of BaSO4 and Na3Ca2(SO4)3F, etc. The water of crystallization decomposes at 554.7°C. The Na3Ca2(SO4)3F decomposes into the composite sulfate and CaF2 over a wide range of temperatures. The main mineral of aegirite(NaFe+3Si2O6) reacts with CaF2 into NaF gas at 993.4°C. The sodium pyroxenite gangue is melts and releases a small amount of SiF4 gas in the range of 1193.5-1300.7°C.

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