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Abstract  

Some new and bis-hydrazine lanthanide glyoxylates Ln[OOC-CHO]3(N2H4)2 where Ln=La, Ce, Pr, Nd, Sm, Eu, Gd, Tb or Dy have been prepared and the compositions of the complexes have been determined by chemical analysis and elemental analysis. The magnetic moment and electronic spectra suggest except Ln3+ which is diamagnetic and all the other complexes are paramagnetic. Infrared spectral data indicate the bidentate coordination of carboxylates group is coordinate to lanthanide ion in a monodentate fashion. However, as a whole, glyoxylate ion acts as a bidentate ligand. The curves of all the complexes show multi-step degradation and the final products are found to be the respective metal oxides. The final residues were identified by their metal analysis, infrared spectra and the X-ray powder diffraction patterns. X-ray powder patterns of the complexes are almost super-imposable as expected which is in favour of isomorphism among the series.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
Y. Kobayashi
,
Y. Tsuruoka
,
M. Kubo
,
H. Nonaka
,
Y. Yamada
,
Y. Sakai
,
H. Shoji
,
W. Sato
,
A. Shinohara
,
Y. Watanabe
, and
H. Matsue

Abstract  

In order to investigate the physical and chemical effects of neutron capture reaction, a neutron in-beam Mössbauer spectroscopic study on two isomorphs of iron disulfide: pyrite and marcasite, were carried out with a parallel plate avalanche counter at room temperature. In both compounds only two major products accounted for the obtained spectrum: one with Mössbauer parameters close to the parent compound and the other one considered to be a new product. The yield of the parent-like species was different in the two isomorphs.

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Journal of Thermal Analysis and Calorimetry
Authors:
D. Gouveia
,
A. Souza
,
M. de Maurera
,
C. da Costa
,
I. Santos
,
S. Prasad
,
J. de Lima
,
C. Paskocimas
, and
E. Longo

Abstract  

Using the Pechini method, pigments with spinel structure (Zn7Sb2O12)were synthesized by substitution of the cation Zn2+ by Co2+, in compounds with different concentrations of Sb2O3. The doping resulted in CoxZn(7–x)Sb2O12 phases(x=1–7) that were isomorphs to spinel, denominated as samples A and B. After thermal treatment at 400C for 1 h, the powders were characterized by thermogravimetry(TG) and differential thermal analysis (DTA). The results indicate a different behavior whena higher amount of Sb2O3 is used, due to the presence of a secondary phase (ilmenite).

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Hydrazinium metal glycinates [(N2H5 2M(NH2CH2COO)4] and bis(hydrazine)metal glycinates, [M(NH2CH2COO)2(N2H4)2], whereM=Co, Ni or Zn have been prepared and characterized by chemical analyses, magnetic moments and vibrational and electronic spectra. The thermal behaviour of these compounds has been studied by thermogravimetry and differential thermal analyses. These complexes decompose with high exothermicity giving metal powder as the final residue. The X-ray powder data of each set of complexes show isomorphism among themselves.

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Abstract  

Adducts of Co(II), Ni(II), Cu(II), Zn(II) and Pb(II) saccharinates with 1,10-phenathroline were synthesized and their thermoanalytical (TG, DTG and DTA) curves in the 20–1000C temperature interval and static air atmosphere were recorded. The complexes are best represented as M(C12H8N2)x(C7H4NO3S)2yH2O (x=2, 2, 2, 2 and 1; y=1, 1, 2, 1 and 2 for M=Co, Ni, Cu, Zn and Pb, respectively). The decomposition of the compounds regularly started with dehydration, followed by loss of the phenanthroline ligand(s). The structures of the Cu and Pb complexes are notably different from other compounds. FTIR spectra of the title compounds in the region of the OH, CO and SO2 stretching vibrations were also studied. The pronounced similarity of the spectra of Co, Ni and Zn adducts indicates possible isomorphism among them.

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The hydrazinium(1+) metal acetates and malonate dihydrates of the molecular formula [(N2H5)2M(CH3COO)4] and (N2H5)2[M(OOCCH2COO)2(H2O)2] respectively, whereM=Co, Ni or Zn, have been prepared and characterized by chemical analyses, conductance, magnetic, spectral, thermal and X-ray powder diffraction studies. The magnetic moments and electronic spectra indicate that these complexes are of high-spin octahedral variety. The infrared spectra show that the hydrazinium ions are coordinated in the case of acetate complexes, whereas in the malonate complexes the hydrazinium ions are out side the coordination sphere. These complexes undergo exothermic decomposition in the temperature range 150–450°C to give the respective metal oxide as the final residue. The X-ray powder diffraction patterns of the malonate complexes indicate isomorphism among them.

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Abstract  

The binary systems of urea with polyethylene glycols 6000 and 4000 show inclusion compounds with higher melting points than the two components (m.p. 143 and 142.5°C resp.). From the melt unstable forms crystallize beside the stable crystal modifications. These have also been identified by FTIR microscopy and X-ray powder diffractometry. The phase diagrams are uncommon in so far as the inclusion compounds do not form eutectics but monotectics with both components. The inclusion compounds of the two polyethylene glycols with urea are isomorphous and form a series of mixed crystals following the Roozeboom I type of diagram.

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Abstract  

Some bis-hydrazine metal pyruvates of transition metal ions of the formula M[CH3COCOO]2 [N2H4]2, where M = Co, Ni, Zn or Cd, tris-hydrazine metal pyruvates of the formula M[CH3COCOO]2 [N2H4]3, where M = Co, Ni, Zn or Cd, and hydrazinium metal pyruvates [N2H5]2M[CH3COCOO]4, where M = Co or Ni have been prepared and the compositions of the complexes have been determined by chemical analysis. The magnetic moments and electronic spectra of the complexes suggest a high-spin octahedral geometry for them. Infrared spectral data of bis-hydrazine complexes indicate the bidentate bridging mode shown by hydrazine molecules and mono dentate coordination by pyruvate ions. However, in tris-hydrazine complexes the pyruvate ions are ionic in nature. In hydrazinium complexes two hydrazinium ions and four pyruvate ions show unidentate coordination mode resulting in six coordination around metal ions. Thermo gravimetry and differential thermal analysis in air reveal that most of the complexes decompose in one step to give the respective metal carbonate as the final residue. However, the hydrazinium complexes yield Co2O3 or NiO as the residue. The final residues were identified by their X-ray powder data. The X-ray powder diffraction patterns of each series of complexes reveal isomorphism among the series.

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Abstract  

The new hydrazinium lanthanide metal complexes of 2-pyrazinecarboxylic acid (HpyzCOO) of the formulae (N2H5)2[Ln(pyzCOO)5] · 2H2O (1), where Ln = La or Ce and (N2H5)3[Ln(pyzCOO)4(H2O)] · 2NO3 (2), where Ln = Pr, Nd, Sm or Dy have been synthesized and characterized by physico-chemical methods. The IR absorption bands of N–N stretching at 960 cm−1 unambiguously prove the existence of N2H5 + ions. The bonding parameters β, b1/2, % δ and η, have been calculated from the electronic spectroscopic (hypersensitive) bands of Pr(III) and Nd(III) complexes. All the complexes undergo endothermic followed by exothermic decomposition to leave the respective metal oxides as the end products. However, the DTA of the complexes 2 demonstrate rather sharp peak than the complexes 1, owing to overwhelming exothermicity, which may be due to the loss of both hydrazine and nitrate moieties in the same step. The X-ray powder diffraction studies reveal the existence of isomorphism among the member complexes.

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Combination of three techniques of thermal analysis (hot stage polarising microscope, DSC, Guinier-Lenne) enabled the determination of the polymorphic behaviour of tetra 1,2,4,5-X benzene (X=Cl, Br). Thermal, calorimetric and crystallographic characterizations have been carried out.

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