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1.
The methods of TG, DTA and DSC were used to study the thermal decompositions of [Ni(H2O)6](NO3)2 and [Ni(D2O)6](NO3)2 in an atmospheric air medium. Intermediates were isolated at 145, 230 and 245°, and were identified by quantitative analysis and IR spectroscopy. The following phase transitions were observed under the conditions of the experiment: melting of the salts, partial dehydration to the tetrahydrate, formation of basic nickel nitrate hydrate stable within a narrow temperature interval, and formation of NiO.
Zusammenfassung Mittels TG, DTA und DSC wurde die thermische Zersetzung von [Ni(H2O)6](NO3)2 und [Ni(D2O)6](NO3)2 in Luft untersucht. Bei Temperaturen von T=145°C, 230°C un 245°C konnten Intermediäre festgestellt werden, welche mittels quantitativer Analyse und IR-Spektroskopie identifiziert wurden. Unter den gegebenen experimentellen Bedingungen wurden folgende Phasenumwandlungen beobachtet: Schmelzen der Salze, partielle Dehydratation zu Tetrahydrat, Bildung von basishem Nickelnitrat-hydrat (stabil innerhalb eines schmalen Temperaturintervalles), schließliche Bildung von NiO.Aus den DSC-Daten wurden die Enthalpien der Phasenumwaldungen berechnet. DTA- und DSC-Daten zeigen, daß die Phasenunwandlungen bei [Ni(H2O)6](NO3)2 bei etwas niedrigeren Temperaturen liegen als bei [Ni(D2O)6](NO3)2.
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2.
The analysis of dehydration of the complexes, [La(C8H8NO3)3.2H2O] and [Yb(C8H8NO3)3.3H2O] for the evaluation of kinetic parameters (Z, E &S *) and mechanism of dehydration by non-isothermal methods are reported. The complexes decompose in three well defined steps involving random nucleation mechanism. First two steps involving the dehydration and the third step the loss of the ligand moiety. The intermediates formed during decomposition were found to be unstable for carrying out any significant studies.
Zusammenfassung Zwecks Ermittlung der kinetischen Parameter (Z, E undS *) und des Mechanismus der Dehydratierung durch nichtisotherme Verfahren wird die Analyse der Dehydratierung der Komplexe [La(C8H8NO3)3·2H2O] und [Yb(C8H8NO3)3·3H2O] beschrieben. Die Komplexe zersetzen sich in drei gut definierten Schritten mit Random-Keimbildungsmechanismus. Die ersten zwei Schritte beinhalten die Dehydratierung, der dritte Schritt den Verlust der Liganden. Die wÄhrend der Zersetzung entstandenen Zwischenprodukte erwiesen sich für jegliche signifikante Untersuchung als zu unstabil.
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3.
The values of the kinetic parametersE andA were determined by Kissinger's method on the basis of the DTA, DTG and DSC curves of particular stages of the thermal decomposition of [Co(NH3)6]2(C2O4)3· 4H2O in air and argon atmospheres. It is shown that the use of Kissinger's method for different kinds of experimental curves (DTA, DSC, DTG) leads to close results.
Zusammenfassung Für verschiedene Schritte der thermischen Zersetzung von [Co(NH3)6]2(C2O4)3· 4H2O in Luft bzw. Argon wurden nach dem Kissinger-Verfahren auf der Basis von DTA-, DTG- und DSC-Kurven Werte für die kinetischen ParameterE undA ermittelt. Es wurde gezeigt, daß das Kissinger-Verfahren für die verschiedenen Arten von experimentellen Kurven (DTA, DSC, DTG) genaue Ergebnisse liefert.
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4.
A computer-aided technique based on Tast polarography is examined for the determination of kinetic parameters of electrode reactions. It is particularly useful for the investigation of unstable species because of the simple and rapid processing of data. Kinetic parameters of cobalt(III)—ammine complexes at mercury electrodes are given for [Co(NH3)6]Cl3, [Co(H2O)(NH3)5](ClO4)3, [Co(NO3)(NH3)5](NO3)2 [CoF(NH3)5](Cl04)2, [Co(C03)(NH3)5] NO3 ,cis-[Co(H2O)2(NH3)4] (Cl04)3 [Co(CO3)(NH3)4] NO3 · 0.5H20, [Co(ox)(NH3)4]Cl · H20, and NH4[Co(ox)2(NH3)2] · H2O, which are obtained in solutions containing 0.1 M acetate buffer and 0.005% gelatin at 25°C.  相似文献   

5.
Kinetic parameters (apparent activation energy, reaction order, pre-exponential factor (Z) in the Arrhenius equation) for thermal decomposition of the [Co(NH3)6]Cl3, Co[(NH3)4Cl2]Cl, K3[Fe(C2O4)3]3H2O and Fe(CH3COO)3 are reported. They have been calculated on the DTA and TG data according to Coats-Redfern's model. Both, decomposition data obtained in argon and in air atmosphere have been considered and the results are compared.
Zusammenfassung Es werden die kinetischen Parameter (scheinbare Aktivierungsenergie, Reaktionsordnung, prÄexponentieller Faktor (Z) der Arrhenius-Gleichung) der thermischen Zersetzung von [Co(NH3)6]Cl3, [Co(NH3)4Cl2]Cl, K3[Fe(C2O4)3]3H2O und Fe(CH3COO)3 beschrieben, die entsprechend dem Coats-Redfern-Modell auf der Basis der DTA- und TG-Daten errechnet wurden. Die Zersetzung wurde sowohl in Argon als auch in Luft durchgeführt und die erhaltenen Daten miteinander verglichen.


Helpful comments from Professor W. Wojciechowski and financial support from Institute for Low Temperatures and Structure Research Polish Academy of Sciences (CPBP 01.12) are greatefully acknowledged.  相似文献   

6.
[Co(NH3)6](NO3)3 (I) dissolved in liquid NH3 reacts with 1 equivalent of KNH2 forming the trinuclear complex [(H3N)4Co(NH2)2Co(NH3)3NH2Co(NH3)5](NO3)5 (II) and the binuclear complex [(H3N)4Co(NH2)2Co(NH3)4](NO3)4 (III). The cleavage of II with diluted acetic acid + Na2SO4 results in the formation of [(H3N)4Co(NH2)2Co(NH3)3 OH2](SO4)2 · 2 H2O (IV) and [Co(NH3)6]3+ isolated as the nitrate I. IV could be transformed to III, which gives trans-[Co(NH3)4Cl2]Cl when reacting with a mixture of conc. HCl and H2SO4. From the obtained results one may infer that the ammonolysis of I corresponds to the hydrolysis of hexaquoxomplexes of trivalent cations in the course of which polynuclear complexes are also formed.  相似文献   

7.
The processes of thermal dehydration and decomposition of Mn(NO3)2 ·.6H2O and its deuterated analogue were studied by DTA, TG and DSC. Comparisons were made between the data obtained for the two compounds. The following phase transitions were observed: melting of the compound; dehydration to monohydrate; dehydration of the monohydrate, accompanied by its partial decomposition to MnO2; and decomposition of the anhydrous nitrate to MnO2.The DSC data were used to determine the enthalpies of the phase transitions, and those corresponding to the partial dehydration were compared with the calculated ones. The formal kinetic parameters (E * andA) for the three stages (without the melting stage) were calculated from the TG curves, and the corresponding kinetic equations are reported.
Zusammenfassung Mittels DTA, TG und DSC wurde der Verlauf der thermischen Dehydratation und Zersetzung von deuteriertem und undeuteriertem Mn(NO3)2·6H2O untersucht und die erhaltenen Ergebnisse beider Verbindungen miteinander verglichen. Folgende Phasenumwandlungen konnten beobachtet werden: Schmelzen der Verbindung; Dehydratation bis zum Monohydrat; Dehydratation des Monohydrates unter teilweiser Zersetzung zu MnO2; Zersetzung von wasserfreiem Nitrat zu MnO2. DSC-Daten wurden zur Bestimmung der Enthalpien für die Phasenumwandlungen benutzt, die so ermittelten Ergebnisse für die partielle Dehydratation wurden mit den berechneten verglichen. Anhand der TG-Kurven wurden die formellen kinetischen Parameter (E * undA) der drei Schritte (ohne Schmelzvorgang) berechnet und die entsprechenden kinetischen Gleichungen beschrieben.
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8.
Transition metal sulfite hydrazine hydrates, MSO3·xN2H4·yH2O whereM=Mn, Fe, Co, Ni and Zn have been prepared and characterized by chemical analysis, infrared spectra, thermoanalytical and combustion studies. The colours,x andy parameters of the complexes varied depending upon the preparation conditions. Thermal decomposition characteristics differ from metal to metal yielding metal oxides at relatively low temperatures.
Zusammenfassung Mittels chemischer Analyse, IR-Spektren, thermoanalytischen und Verbrennungsstudien wurden die Hydrazinhydrate der hergestellten Übergangsmetallsulfite MSO3·xN2H4·yH2O mitM=Mn, Fe, Co, Ni und Zn beschrieben. Farbe sowie die Parameterx undy der Komplexe hängen von den Herstellungsbedingungen ab. Die thermische Zersetzung, bei der bei relativ niedrigen Temperaturen Metalloxide entstehen, ist von Metall zu Metall verschieden.
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9.
The thermal decomposition of the complexes: [Fe(C17H24O4)1.5·2H2O]n and [UO2(C17H24O4·2H2O]n, and evaluation of kinetic parameters (E, Z andS) by making use of Piloyan-Novikova, Coats-Redfern and Horowitz-Metzger equations are reported. The complexes are found to decompose in three well defined steps involving random nucleation mechanism. The intermediates formed during decomposition usually undergo further decomposition without remaining stable over a considerable range of temperature.
Zusammenfassung Es wird über die thermische Zersetzung der Komplexe [Fe(C17H24O4)1.5·2H2O]n und [UO2(C17H24O4)·2H2O]n und über die Ermittlung der kinetischen Parameter durch Anwendung der Piloyan-Novikova, der Coats-Redfern und der Horowitz-Metzger-Gleichungen berichtet. Die Komplexe werden in drei gut definierten Stufen mit Random-Keimbildungsmechanismus zersetzt. Die während der Zersetzung gebildeten Zwischenprodukte unterliegen stets einer weiteren Zersetzung, ohne in einem erheblichen Temperaturbereich Stabilität zu zeigen.
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10.
Density functional theory (B3LYP, B3LYP-D3, wB97XD, M062X, and M06L) and ab initio methods (MP2 and CCSD(T)) in conjunction with 6-31+G(d,p) and LanL2DZ were employed to investigate the interaction energies between [Co(NH3)5NO2]2+ linkage isomers and chloride and nitrate in both gas phase and solid state. The nature of the chemical bonding has been analyzed by means of the atoms in molecules, electron density shift, natural bond orbitals, symmetry adapted perturbation theory, and energy decomposition analysis. The electronic structures of the two lowest laying singlet states (So and S1) of [Co(NH3)5NO2](NO3)Cl isomers were also investigated using CASSCF(6,6) with LanL2DZ and 6-31G(d) basis sets. Our results show that [Co(NH3)5NO2]2+ linkage isomers interact more strongly with chloride than nitrate. The structures of [Co(NH3)5NO2](NO3)Cl linkage isomers and their relative stabilities were examined in gas phase and in solid state and confirmed the nitro-complex as the most stable following by a viable intermediate endo-complex. Study of the nitro-nitrito linkage isomerization in [Co(NH3)5NO2](NO3)Cl revealed that anions form strong electrostatic bonds with [Co(NH3)5NO2]2+ leading to decrease in an activation energy compared to the [Co(NH3)5ONO]2+ isomers. A concerted action of ionic interactions and hydrogen bonds are suspected of regulating the isomerization in solid state. Assessment of various DFT methods with respect to CCSD(T) suggests M062X suitable method for [Co(NH3)5NO2](NO3)Cl linkage-isomerization study. Potential energy surface calculations at the CASSCF/6-31G(d) level of theory shows that the conical intersection (S1/So) might play an important role in the photoisomerization of [Co(NH3)5NO2](NO3)Cl.  相似文献   

11.
Anisaldehyde Girard T complexes of Mn(II), Fe(III), Co(II) and Cu(II) with the general formula [MCl2(AGT)2]Cl2 or [MCl2(AGT)]Cl, where (AGT)=anisaldehyde carbohydrazone methyltrimethylammonium cation, H3C-O-C6H4-CH=N-NHCOCH2N+-(CH3)3 andM=Mn(II), Co(II), Fe(III) or Cu(II) were prepared. Elemental analysis, electrical conductance and IR spectra showed that the ligand coordinates with the studied metals in keto form through the azomethine and carbonyl groups. The molar conductances, electronic spectra and magnetic moments of the solid complexes were determined. The processes of thermal decomposition of these complexes were studied. From the analysis of the thermal decomposition curves obtained, the corresponding kinetic parametersn, E a and logA were evaluated by two different methods and the effects of the central metal ions on the stabilities of the complexes are discussed.
Zusammenfassung Es wurde die Herstellung und Isolierung von Anisaldehyd-G-T-Komplexen von Mn(II), Fe(III), Co(II) und Cu(II) der allgemeinen Formel [MCl2(AGT)2]Cl2 oder [MCl2(AGT)]Cl durchgeführt, wobei (AGT)=Anisaldehydcarbohydrazon-methyl-trimethyl-ammoniumkation H3C-O-C6H4-CH=N-NHCOCH2N+-(CH3)3 undM=Mn(II), Co(II), oder Fe(III) und Cu(II). Elementaranalyse, elektrische LeitfÄhigkeit und IR-Spektren zeigten, da\ der Ligand an den untersuchten Metallen in der Ketoform, über die Azomethin- und Carbonylgruppe koordiniert ist. Es wurden die molare LeitfÄhigkeit, Elektronenspektren und das magnetische Moment der festen Komplexe bestimmt. Der Vorgang der thermischen Zersetzung dieser Komplexe wurde untersucht. Durch Analyse der erhaltenen thermischen Zersetzungskurven wurden die entsprechenden kinetischen Parametern, E a und logA durch zwei verschiedene Methoden ermittelt und weiterhin der Einflu\ des zentralen Metallions auf die StabilitÄt der Komplexe diskutiert.


The authors would like to express their sincere thanks to Dr. F. I. M. Taha, Professor of Inorganic Chemistry and Head of the Chemistry Department, Faculty of Science, Mansoura University, for encouragement and useful discussions.  相似文献   

12.
The thermal decompositions of polycrystalline samples of [Ni(NH3)6](NO3)2 were studied by thermogravimetric analysis with simultaneous gaseous products of the decomposition identified by a quadruple mass spectrometer. Two measurements were made for samples placed in alumina crucibles, heated from 303 K up to 773 K in the flow (80 cm3 min?1) of Ar 6.0 and He 5.0, at a constant heating rate of 10 K min?1. Thermal decomposition process undergoes two main stages. First, the deamination of [Ni(NH3)6](NO3)2 to [Ni(NH3)2](NO3)2 occurs in four steps, and 4NH3 molecules per formula unit are liberated. Then, decomposition of survivor [Ni(NH3)2](NO3)2 undergoes directly to the final decomposition products: NiO1+x, N2, O2, nitrogen oxides and H2O, without the formation of a stable Ni(NO3)2, because of the autocatalytic effect of the formed NiO1+x. Obtained results were compared both with those published by us earlier, by Farhadi and Roostaei-Zaniyani later and also with the results published by Rejitha et al. quite recently. In contradiction to these last ones, in the first and second cases agreement between the results was obtained.  相似文献   

13.
Glutaric dihydrazide (GDH) and adipic dihydrazide (ADH) have been found to react with Co(II) chloride and Ni(II) chloride and nitrate in ethanolic solution to form complexes of the general empirical compositionsMLCl2,ML 2Cl2 and [NiL 2(H2O)2] (NO3)2 whereM=Co(II), Ni(II) andL=GDH,ADH. Tetrahedral geometry has been proposed for 11 complexes of Co(II) and octahedral geometry for the remaining complexes based on measurements of molar conductance, magnetic susceptibility, electronic and ir spectra.
Synthese und Struktur von Co(II)- und Ni(II)-Komplexen von Glutarsäure- und Adipinsäuredihydraziden
Zusammenfassung Glutarsäuredihydrazid (GDH) und Adipinsäuredihydrazid (ADH) bilden mit Co(II)-Chlorid und Ni(II)-Chlorid bzw.-Nitrat in ethanolischer Lösung Komplexe der generellen ZusammensetzungenMLCl2,ML 2Cl2 und [NiL(H2O)2] (NO3)2, mitM=Co(II), Ni(II) undL=GDH,ADH. Für 11-Komplexe von Co(II) wird eine tetragonale Geometrie, für alle anderen Komplexe eine oktaedrische Geometrie vorgeschlagen. Die Basis dazu lieferten Messungen der molaren Leitfähigkeit, der magnetischen Suszeptibilität und der UV- bzw. IR-Spektren.
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14.
    
Zusammenfassung Es wird eine neue mikrogewichtsanalytische Bestimmungsmethode für Beryllium beschrieben, bei der das Beryllium in Form der komplexen Verbindung [Co(NH3)6][(H2O)2 Be2(CO3)2(OH)3]. 3H2O gewogen wird.Das vorgeschlagene Verfahren ist einfach und in der kurzen Zeit von 30–90 min leicht durchführbar.Das Verfahren ist auch zur Bestimmung von Beryllium in Gegenwart von Eisen, Aluminium und Magnesium geeignet, wenn man die Begleitmetalle mittels ÄDTA (Natriumsalz der Äthylendiamintetraessigsäure) maskiert.  相似文献   

15.
The isomorphous title compounds, [Ni{(NH2)2CO}4(H2O)2](NO3)2 and [Co{(NH2)2CO}4(H2O)2](NO3)2, feature discrete centrosymmetric cations in octahedral coordinations, formed by four urea molecules linked via their O atoms to the central ion in equatorial positions and two water molecules in trans positions. The complexes are packed in a pseudo‐hexagonal manner separated by the nitrate counter‐ions. All H atoms are involved in moderate hydrogen bonds of four types: N—H...O=C, N—H...O—N, O—H...O—N and N—H...O—H. Graph‐set analysis was applied to distinguish the hydrogen‐bond patterns at unitary and higher level graph sets.  相似文献   

16.
The complexes Mn(II), Co(II), Ni(II) and Zn(II) with 4-oxo-4H-1-benzopyran-3-carboxaldehyde were synthesized and characterized by elemental analysis, infrared and UV spectroscopy, X-ray diffraction patterns, magnetic susceptibility, thermal gravimetric analysis, conductivity and also solubility measurements in water, methanol and DMF solution at 298 K. They are polycrystalline compounds with various formula and different ratio of metal ion:ligand. Their formula are following: [MnL2(H2O)](NO3)2·2H2O, [CoL2](NO3)2·3H2O, [NiL2](NO3)2·3H2O, [CuL2](NO3)2·H2O and [ZnL3](NO3)2, where L = C10H6O3. The coordination of metal ions is through oxygen atoms present in 4-position of γ-pyrone ring and of aldehyde group of ligand. Chelates of Mn(II), Co(II), Ni(II) and Cu(II) obey Curie–Weiss law and they are high-spin complexes with the weak ligand fields. The thermal stability of analyzed complexes was studied in air at 293–1,173 K. On the basis of the thermoanalytical curves, it appears that thermal stability of anhydrous analysed chelates changed following: Cu (423 K) < Zn (438 K) ~ Co (440 K) < Ni (468 K). The gaseous products of thermal decomposition of those compounds in air atmosphere are following: CO2, CO, NO2, N2O, hydrocarbons and in case of hydrates also water. The molar conductance data confirm that the all studied complexes are 1:2 electrolytes in DMF solution.  相似文献   

17.
Novel oligonuclear complexes of Co(II), Ni(II), and Cu(II) with 4-(3,4-dichlorophenyl)-1,2,4-triazole (L) of the composition [M3L10(H2O)2](NO3)6 (M = Co(II), Ni(II)), [Ni3L6(H2O)6]Hal6 (Hal = Cl?, Br?), and [Cu5L16(H2O)2](NO3)10 · 2H2O were synthesized and studied by magnetic susceptibility, electronic and IR spectroscopy, and powder X-ray diffraction methods. All the above complexes are X-ray amorphous. Antifer-romagnetic exchange interactions between the M2+ ions were discovered in the [Co3L10(H2O)2](NO3)6 and [Ni3L10(H2O)2](NO3)6 complexes, whereas ferromagnetic exchange interactions were observed in the complexes [Ni3L6(H2O)6]Cl6, [Ni3L6(H2O)6]Br6, and [Cu5L16(H2O)2](NO3)10 · 2H2O.  相似文献   

18.
The thermal decompositions of crystalline Co(II), Ni(II) and Zn(II) complexes with thiosalicylic acid or ethylenediamine were investigated via the respective thermal curves. On the basis of the decomposition temperatures, the following sequences of stabilities of the studied compounds have been proposed: 1. [Co(SR)][Ni(SR)]<[Zn(SR)]; 2. [Zn(en)2](NO3)2·2H2O<[Co(en)2](NO3)2<[Ni(en)3](NO3)2.  相似文献   

19.
The evolved gaseous analysis (EGA), infrared spectra, and XRD have been applied to the study of solid state reactions of KSCN with five cobalt(II)-ammine complexes: [Co-(NH3)5N3]Cl2. [Co(NH3)5(NO2)]Cl2. [Co(NH3)5(H2O)]Cl3. [Co(NH3)5Cl]Cl2, and [Co(NH3)6]Cl3 in a hydrogen atmosphere. It is found that the existence of KSCN shifts the thermal decomposition of these complexes to a lower temperature. The corresponding peak temperatures are near 140°C. The effect of KSCN is discussed and kinetic parameters of deammine reactions are calculated.  相似文献   

20.
The novel high nitrogen‐containing energetic complex [Cd(DAT)6](NO3)2 was synthesized by reaction of Cd(NO3)2·6H2O with 1,5‐diamino‐tetrazole (DAT). It was characterized by elemental analysis, FT‐IR spectroscopy and single‐crystal X‐ray diffraction analysis. The central Cd2+ ion is coordinated by six nitrogen atoms from six DAT ligand molecules to form a hexacoordinate distorted octahedral compound. The [Cd(DAT)6](NO3)2 molecules are linked together through two types of hydrogen bonds thus forming a stable three‐dimensional net structure. The thermal decomposition mechanism of [Cd(DAT)6](NO3)2 was investigated by DSC and TG/DTG analyses and FT‐IR spectroscopy. The kinetic parameters of the exothermic process were studied by using Kissinger’s and OzawaDoyle’s methods.  相似文献   

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