Ultramarin-Gelb II: Herstellung und Charakterisierung einer Rarität / Ultramarine-Yellow II: Preparation and Characterization of a Rarity

1987 ◽  
Vol 42 (6) ◽  
pp. 663-665 ◽  
Author(s):  
P. Köhler ◽  
G. Winter ◽  
F. Seel ◽  
K.-P. Klos

Abstract The missing link in the series of ultramarine pigments, a synthetic sodalite containing yellow S2- ions, was prepared by thermal decomposition of a thiocyanate sodalite under vacuum or nitrogen. The nature of the product has been elucidated through X-ray powder analysis, VIS/UV-and ESR-spectrometric measurements, and by the observation of the brilliant red fluorescence of the sulfur radical ion S2-.

1989 ◽  
Vol 44 (5) ◽  
pp. 553-556 ◽  
Author(s):  
Th. Fetzer ◽  
A. Lentz ◽  
T. Debaerdemaeker

Single crystals of Cu(pz)Br2 and Cu(pz)Cl2 were grown by using gel methods with tetramethoxysilane as the gel-forming reagent. Thermal decomposition is interpreted. Crystal data for the bromo complex: monoclinic, space group C2/m with a = 1239.2(3) pm, b = 685.9(2) pm, c = 390.7(3) pm, β = 96,23(5)°. Crystal data for the chloro-complex: monoclinic, space group C2/m with a = 1197.1(3) pm, b = 684.9(3) pm, c = 370.1(3) pm, β = 95.96(5)°. Crystal structure analyses reveal that CuHal2 molecules are bonded by pyrazine to form linear chains. These chains are cross-linked by bridging halogen atoms.


2007 ◽  
Vol 119 ◽  
pp. 71-74 ◽  
Author(s):  
Yan Li ◽  
Xiao Li Zhang ◽  
Young Hwan Kim ◽  
Young Soo Kang

Co nanoparticles were synthesized via a solventless thermal decomposition of Co2+-oleate2. The crystalline structure is strongly affected by the thermal treatment of the Co nanoparticles. Further, the annealing also results in the decomposition of surfactant around Co particles. The size of nanoparticles was confirmed by transmission electron microscopy (TEM). The crystal structure of nanoparticles was characterized by X-ray diffraction pattern (XRD). The magnetic properties were characterized by vibrating sample magnetometer (VSM).


1995 ◽  
Vol 48 (3) ◽  
pp. 557 ◽  
Author(s):  
SJ Crimp ◽  
L Spiccia

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.


1990 ◽  
Vol 45 (2) ◽  
pp. 199-202 ◽  
Author(s):  
Th. Fetzer ◽  
A. Lentz ◽  
T. Debaerdemaeker ◽  
O. Abou-El-Wafa

Single crystals of Cu(pdz)Cl2 were grown by using gel methods with tetramethoxysilane as the gel-forming reagent. Thermal decomposition is interpreted. Crystal data for the complex : monoclinic, space group C2/c with a = 938.3(3) pm, b = 1242.9(3) pm, c = 675.7(4) pm, β = 128.48(5)°. A crystal structure analysis reveals CuCl2 molecules connected by pyridazine in the form of zigzag-chains. Between these chains there are only Van-der-Waals-Interactions.


2016 ◽  
Vol 18 (7) ◽  
pp. 5397-5403 ◽  
Author(s):  
Christoph J. Sahle ◽  
Simon Kujawski ◽  
Arndt Remhof ◽  
Yigang Yan ◽  
Nicholas P. Stadie ◽  
...  

We present an in situ study of the thermal decomposition of Mg(BH4)2 in a hydrogen atmosphere of up to 4 bar and up to 500 °C using X-ray Raman scattering spectroscopy at the boron K-edge and the magnesium L2,3-edges.


2002 ◽  
Vol 58 (5) ◽  
pp. 808-814 ◽  
Author(s):  
Axel Nørlund Christensen ◽  
Rita Grønbæk Hazell ◽  
Ian Charles Madsen

The synthesis of BaC2O4·0.5H2O and its thermal decomposition to α-BaC2O4 and β-BaC2O4 was investigated. BaC2O4·0.5H2O is precipitated at room temperature from aqueous solutions of barium chloride and ammonium oxalate. The deuterated compound BaC2O4·0.5D2O was made in analogy with D2O as the solvent. The compounds were characterized by X-ray and neutron diffraction analysis. Single-crystal X-ray diffraction of BaC2O4·0.5H2O measured at 120 K gave the triclinic cell a = 8.692 (1), b = 9.216 (1), c = 6.146 (1) Å, α = 95.094 (3), β = 95.492 (3), γ = 64.500 (3)°, space group P\bar 1, Z = 4. Two independent Ba atoms are each coordinated to nine O atoms at distances from 2.73 (1) to 2.99 (1) Å. One of the two oxalate ions deviates significantly from planarity. The water molecule does form weak hydrogen bonds. In situ X-ray powder diffraction was used to study the thermal decomposition of BaC2O4·0.5H2O and the formation of α-BaC2O4. The X-ray powder pattern of α-BaC2O4 measured at 473 K was indexed on a triclinic cell with a = 5.137 (3), b = 8.764 (6), c = 9.006 (4) Å, α = 83.57 (4), β = 98.68 (5), γ = 99.53 (5)°, and the space group P\bar 1 with Z = 4.


Minerals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 200 ◽  
Author(s):  
Mizraim Flores ◽  
Iván Reyes ◽  
Elia Palacios ◽  
Francisco Patiño ◽  
Julio Juárez ◽  
...  

Jarosites are widely used in the hydrometallurgical industry of zinc to eliminate iron and other impurities contained in the concentrates. However, these compounds can also incorporate elements of significant environmental concern such as Tl+, Hg2+, Pb2+, Cd2+, Cr(VI), and As(V). In this work, the characterization of a synthetic mercury jarosite and its thermal decomposition kinetics are reported. XRD and FTIR analyses confirm that a mercury jarosite—Hg0.40(H3O)0.2]Fe2.71(SO4)2.17(OH)4.79(H2O)0.44—was successfully synthesized. Four mass loss events were observed by thermogravimetric analysis at 290 °C, 365 °C, 543 °C, and 665 °C. The third event corresponds to mercury decomposition into mercury oxide, whilst the forth is related to the jarosite to hematite transformation determined by X-ray diffraction starting at around 600 °C. According to the kinetic parameters (activation energy and frequency factor) of the thermal decomposition process, the fourth stage required the highest energy (Ea = 234.7 kJ∙mol−1), which corresponds to elimination of sulfur and oxygen from the jarosite lattice. Results show that jarosite-type compounds have the capability to incorporate heavy metals into their structure, retaining them even at high temperatures. Therefore, they can be used as a remediation strategy for heavy metals, such as mercury and others elements of environmental concern.


2012 ◽  
Vol 512-515 ◽  
pp. 2467-2470 ◽  
Author(s):  
Hong Xiao Zhao ◽  
Bao Ming He ◽  
Jing Li ◽  
Hui Min Jia ◽  
Li Wei Mi

In this paper, NiCo2O4 nanoparticles were synthesized by three different methods. The applied preparation methods in this research are thermal decomposition of a mixed oxalate precursor, combustion synthesis and hydrothermal method. The crystalline phase, morphology and specific surface area (BET) of the resultant samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and nitrogen physical adsorption, respectively. The research found that the hydrothermal method is a promising method to prepare NiCo2O4 nanoparticles.


2007 ◽  
Vol 72 (12) ◽  
pp. 1281-1293 ◽  
Author(s):  
Vukadin Leovac ◽  
Zoran Tomic ◽  
Katalin Mészáros-Szécsényi ◽  
Ljiljana Jovanovic ◽  
Milan Joksovic

The crystal and molecular structures of four tetrahedral structurally similar [Co(aamp)2X2] complexes (aamp = 4-acetyl-3-amino-5-methylpyrazole, X = Cl, Br, I and NCS) were determined by X-ray diffraction analysis and are discussed in detail. It was found that the different capacity of the ligand X (NCS vs. Cl, Br, I) for the formation of non-bonding contacts influence the mode of molecular association in the solid state. The complexes were characterized by UV-Vis spectroscopy. The first step of the thermal decomposition of the compounds was checked and is discussed in the view of the IR spectrum of the intermediate isolated from [Co(aamp)2Br2] by the quasi-isothermal technique.


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