共查询到20条相似文献,搜索用时 15 毫秒
1.
E. Ingier-Stocka 《Journal of Thermal Analysis and Calorimetry》1991,37(4):769-776
The thermal decomposition of [Co(NH3)5Cl]Cl2 was studied under non-isothermal conditions, in dynamic air and argon atmospheres. The kinetics of the particular stages of [Co(NH3)5Cl]Cl2 thermal decomposition were evaluated from the dynamic weight loss data by means of the modified Coats-Redfern method. TheD n andR n models were selected as the models best fitting the experimental TG curves. These models suggest that the kinetics and macromechanism of [Co(NH3)5Cl]Cl2 decomposition can be governed by diffusive and/or phase boundary processes. The values of the activation energy,E a, and the pre-exponencial factor,A, of the particular stages of the thermal decomposition were calculated. 相似文献
2.
E. Ingier-Stocka 《Journal of Thermal Analysis and Calorimetry》1991,37(3):521-532
Simultaneous TG-DTG-DTA studies on [Co(NH3)5Cl]Cl2 under non-isothermal conditions were carried out in dynamic air and argon atmospheres in the temperature range 293–1273 K. Thermogravimetric measurements under quasi-isothermal conditions were also made. On the basis of the experimental data (weight loss, X-ray diffraction, reflectance spectroscopy and chemical analysis), the probable decomposition sequences are presented. The data indicate that the thermal decomposition of [Co(NH3)5Cl]Cl2 occurs in three stages in argon and four stages in air.The changes in the morphology of crystalline [Co(NH3)5Cl]Cl2 powder in the course of its thermal decomposition in air were followed by scanning electron microscopy.
Zusammenfassung In dynamischer Luft- und ArgonatmosphÄre wurden im Temperaturbereich 293–1273 K unter nichtisothermen Bedingungen simultane TG-DTG-DTA Untersuchungen an [Co(NH3)5Cl]Cl2 durchgeführt, ebenso auch thermogravimetrische Untersuchungen unter quasi-isothermen Bedingungen. Auf der Grundlage der experimentellen Daten (Gewichtsverlust, Röntgendiffraktion, Reflexionsspektroskopie und chemische Analyse) wurde eine wahrscheinliche Zersetzungssequenz erstellt. Es zeigte sich, da\ die thermische Zersetzung in Argon in drei Schritten, in Luft dagegen in vier Schritten verlÄuftDie VerÄnderung der Morphologie kristallinen [Co(NH3)5Cl]Cl2-Pulvers im Verlaufe seiner thermischen Zersetzung in Luft wurde durch Scanning-Elektronenmikroskopie verfolgt.相似文献
3.
The heat capacity of [Fe(2-pic)3]Cl2·C2H5OH Crystal (2-pic: 2-picolylamine) has been measured with an adiabatic calorimeter between 13 and 315 K. Two phase transitions centered at 114.04 and 122.21 K were observed. This finding accords with recent prediction of possible existence of two-step spin-conversion (H. Köppen et al., Chem. Phys. Lett., 91 (1982) 348). The total transition enthalpy and entropy amounted to ΔH = 6.14 kJ mol?1 and ΔS = 50.59 J K?1 mol?1. The transition entropy consists of the magnetic contribution (13.38 J K?1 mol?1), the orientational order-disorder phenomenon of the solvate ethanol molecule (8.97) and the change in the phonon system, in particular the change in stretching and deformation vibrations of the metal-ligand (28.24). 相似文献
4.
The crystal structure of the spin crossover complex [Fe(2-pic)3]Cl2·EtOH in its high spin state (298, 150 K) and low spin state (90 K) has been determined. The crystals are monoclinic, P21/c with Z=4 in the two spin states. Pronounced changes in the FeN bond distance (2.195 A for high spin, 2.013 A for low spin on average) and orientational disorder of the ethanol molecule were observed. The complexes and ethanols are both hydrogen bounded to Cl? ions. 相似文献
5.
《Journal of Coordination Chemistry》2012,65(9):1009-1019
The electrochemical behavior of Co(creatinine)2Cl2 was investigated by cyclic voltammetry in organic solvents (DMSO and DMF) and in aqueous solution. Analysis of the results indicates that the electroactive species depend on the nature of the solvent. In DMF a single reduction process Co(II)/Co(I) is observed. In DMSO the redox behavior of the complex changes with the scan rate and a two-electron transfer process can be eventually observed. In aqueous solution the complex immediately decomposes giving rise to the aquo-cation. The characteristic peak of the redox couple Cl2/Cl? is observed as a consequence of the chloride released from the coordination sphere. Analysis of the electronic spectra gave additional support to the proposed mechanisms. The Co-Cl and Co-N stretching bands were clearly identified in the low frequency region of the IR spectrum. 相似文献
6.
R. Wojciechowska P. Bragiel M. Czerwinski 《Journal of Thermal Analysis and Calorimetry》1990,36(4):1295-1306
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.
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
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
7.
《Solid State Sciences》2005,7(1):13-15
Co3O4 nanorods were successfully synthesized from a single precursor via a thermal decomposition and oxidization route. The precursor used was Co(CO3)0.35Cl0.20(OH)1.10, which was prepared by a hydrothermal reaction using CoCl2⋅6H2O with CO(NH2)2 at 95–120 °C. Both the precursor and the as-prepared Co3O4 were characterized with XRD, TEM, SEM, TGA and XPS. The precursor, as well as Co3O4, was found to be composed of nanorods that were radially bunched. The Co3O4 nanorods obtained through a thermal treatment at 300 °C for 5 h were found to have a porous structure. 相似文献
8.
H. Köppen E.W. Müller C.P. Köhler H. Spiering E. Meissner P. Gütlich 《Chemical physics letters》1982,91(5):348-352
The spin transition in [Fe(2-pic)3]Cl2·EtOH (2-pic = 2-picolylamine) has been reinvestigated by Mössbauer spectroscopy and magnetic susceptibility measurements. With both techniques we see a “two-step” spin conversion in the crossover region with transition temperatures at 120.7 and 114.0 K. This has never been reported for any other spin crossover system. The quadrupole splittings for both spin states change abruptly in the range of the transition. 相似文献
9.
10.
The compound [Co(En)3]2[Hg2(H2O)Cl6]Cl4 (I, En is ethylenediamine) has been synthesized and studied by X-ray diffraction. The crystals of I (a = 21.8745(14) Å, b = 10.6008(6) Å, c=15.4465(12) Å, space group Pna21) consist of tris(ethylenediamine)cobalt(III) complexes (the unit cell contains two [Co(En)3]3+ cations of opposite chirality). [Hg2(H2O)Cl6]2? anions, and isolated chloride ions. The complex anion consists of the tetrahedral [HgCl4]2? group (Hg-Cl, 2.44–2.56 Å) and the hydrated molecule [Hg(H2O)Cl2] (Hg-Cl, 2.301 and 2.308 Å; Hg-O, 2.788 Å) combined by weak Hg-Cl interactions (2.915 and 3.220 Å). 相似文献
11.
Megan R. Kollitz A. Graham Lappin Allen G. Oliver 《Acta Crystallographica. Section C, Structural Chemistry》2023,79(5):164-169
The structures of three racemic double salts of [Co(en)3]Cl3 (en is ethane-1,2-diamine, C2H8N2), namely, bis[tris(ethane-1,2-diamine-κ2N,N′)cobalt(III)] hexaaquasodium(I) heptachloride, [Co(en)3]2[Na(H2O)6]Cl7, bis[tris(ethane-1,2-diamine-κ2N,N′)cobalt(III)] hexaaquapotassium(I) heptachloride, [Co(en)3]2[K(H2O)6]Cl7, and ammonium bis[tris(ethane-1,2-diamine-κ2N,N′)cobalt(III)] heptachloride hexahydrate, (NH4)[Co(en)3]2Cl7·6H2O, have been determined, and the structural similarities with the parent compound, tris(ethane-1,2-diamine-κ2N,N′)cobalt(III) trichloride tetrahydrate, [Co(en)3]Cl3·4H2O, are highlighted. All four compounds crystallize in the trigonal space group Pc1. When compared with the parent compound, the double salts show a modest increase in the unit-cell volume. The structure of the chiral derivative [Λ-Co(en)3]2[Na(H2O)6]Cl7 has also been redetermined at cryogenic temperatures (120 K) and the disorder noted in a previous report has been accounted for. 相似文献
12.
A. Leineweber H. Jacobs R. Eßmann P. Allenspach F. Fauth P. Fischer 《无机化学与普通化学杂志》2001,627(9):2063-2069
Diammine cobalt(II) chloride, Co(N(H, D)3)2Cl2 was prepared by decomposition of the corresponding hexaammines at 120 °C in dynamical vacuum. Crystal structures and magnetic properties of these materials were characterised by X‐ray and neutron powder diffraction, and heat capacity measurements. At ambient temperatures Co(N(H, D)3)2Cl2 crystallises in the Cd(NH3)2Cl2 type structure: space group Cmmm, Z = 2, a = 8.0512(2) Å, b = 8.0525(2) Å, c = 3.73318(9) Å (X‐ray data of the H compound). This structure consists of chains of edge‐sharing octahedra [CoCl4/2(NH3)2] running along the c‐axis. Neutron diffraction confirms that that the ND3 groups are rotationally disordered at ambient temperatures. At 1.5 K and 20 K neutron diffraction data reveal rotational ordering of the ND3 groups leading to doubling of the c‐axis and to Ibmm symmetry: a = 7.9999(6) Å, b = 7.9911(5) Å, c = 7.4033(3) Å (Z = 4, values for T = 1.5 K). Furthermore, antiferromagnetic ordering is present at these temperatures. It is caused by a ferromagnetic coupling of the magnetic moments at Co2+ (3.60(5) μB at 1.5 K, 3.22(5) μB at 20 K) along the octahedra chains [CoCl4/2(NH3)2] and antiferromagnetic coupling between neighbouring chains. According to heat capacity measurements the phase transition antiferromagnetic‐paramagnetic takes place at TN = 26 K. 相似文献
13.
The ruthenium(II) complex used as a catalyst in reactions of alcohols and Et3SiH proved to be the dimer [(CH3)3PRu(CO)2Cl2]2 and not the complex [(CH3)3P]2 Ru(CO)2Cl2. Both complexes were prepared, characterized and their catalytic properties were compared. 相似文献
14.
Preparation and Crystal Structure of Tris(ethylenediamine) cobalt(III)-trichlorostannate(II)-dichloride, [Co(en)3] [SnCl3]Cl2 The title compound has been prepared from [Co(en)3]Cl3 and SnCl2 · 2H2O in aqueous HCl solution. It crystallizes in the orthorhombic space group Pbca, with a = 21.906(7), b = 10.607(3), c = 15.356(7) Å. The crystal structure has been determined from 1606 independent reflections by Patterson snd Fourier syntheses, and has been refined by least squares methods to R = 0.074. The [Co(en)3]3+ ion is found to have the conformation of Λ(δδλ) resp. Δ(λλδ). The structure of the [SnCl3]? ion corresponds to a distorted tetrahedron, in which one site is occupied by the stereochemically active 5s electron pair. The following Sn? Cl distances have been found 2.493(7), 2.492(5), 2.479(7) Å, the distances of the two anionic Cl atoms from Sn are >4 Å. 相似文献
15.
The crystal structures of Ni(NCNH2)4Cl2 and Co(NCNH2)4Cl2, the first complexes with cyanamide as a neutral ligand, have been determined from single crystal data (Im3m, Z = 6, a = 1259.3(2) pm, R1 = 0.0245 for Ni(NCNH2)4Cl2 and a = 1266.3(2) pm, R1 = 0.0241 for Co(NCNH2)4Cl2; both 329 intensities and 23 parameters). Ni2+ and Co2+ are octahedrally coordinated by four equatorial H2NCN molecules and two axial chloride ions, and the 20 and 19 electron octahedral complexes are connected by a network of hydrogen bonds. The cyanamide ligands are slightly bent (166°), and the two N–C distances are 112 and 133 pm. Ni(NCNH2)4Cl2/Co(NCNH2)4Cl2 are Curie paramagnets with two/three unpaired electrons. 相似文献
16.
《Solid State Sciences》2004,6(6):519-522
The new compound Co6(TeO3)2(TeO6)Cl2 has been isolated during an investigation of the system CoO:CoCl2:TeO2. The new compound is deep purple in color and crystallizes in the tetragonal system, space group P42/mbc, a=8.3871(7) Å, c=18.5634(19) Å, Z=4. The Co(II) ions have octahedral [Co1O6] and tetrahedral [Co2O3Cl] coordinations. Tellurium is present both as Te(IV) with a tetrahedral [Te1O3E] coordination, where E is the 5s2 lone-pair and as Te(VI) with an octahedral [Te2O6] coordination. The structure is made up of intersecting layers of tetrahedra forming channels comprising octahedra chains that run along the c-axis. The new compound is the first cobalt tellurium oxochloride described. 相似文献
17.
K. V. Yusenko S. A. Gromilov I. A. Baidina I. V. Korol'kov V. V. Zhivonitko A. B. Venediktov S. V. Korenev 《Journal of Structural Chemistry》2003,44(1):60-67
Binary complex salts of M(NH3)5Cl]2[IrCl6]Cl2 composition, where M = Co(III), Rh(III), or Ir(III), have been studied. All phases are isostructural with [M(NH3)5Cl]2[PtCl6]Cl2 complexes [M = Rh(III) and Ir(III)]; Xray structural and crystallochemical analysis have been performed. 相似文献
18.
An X-ray diffraction analysis was performed for crystalline [Co(Dien)2]Hg2Cl7 (a = 14.452(2), b = 9.831(1), c = 15.967(2) åΒ = 97.17(1)?, space group P21/c, Z = 4) and [Co(Dien)HGlygly]Hg2Cl6 (a = 7.693(1), b = 14.439(2), c = 19.961(2) å, Β = 100.31(1)?, space group P21 Z = 2), where Dien is diethylenetriamine and HGlygly is the glycylglycine anion [H2NCH2C(OH) = NCH2CO2]. The anionic moiety is represented by isolated centrosymmetric ions [Hg4Cl14]6- in the former and by infinite chains [Hg2Cl6] n 2n- in the latter (the chain is composed of two alternating vertex-sharing nonequivalent tetrahedral groups HgCl4. In the cobalt(III) complex cations, the extreme donating atoms of the Dien and HGlygly ligands are in the trans positions of the coordination octahedron. 相似文献
19.
W.W. Wendlandt 《Thermochimica Acta》1980,37(1):89-96
The thermal dissociation of the [Co(NH3)6]X3 (X = Cl?, Br?, I?, and NO?3), [Co(en)3]X3 (X = Cl?, Br?, I?, NO?3, HSO?4 and C2O2?4), cis- [Co(en)2Cl2]Cl, and trans-[Co(en)2ClBr]NO3 complexes was investigated by an electrical conductivity (EC) technique. During the thermal dissociation reactions, liquid or semi-liquid phases are formed which cause large increases in the EC of the compound. The effect of concentration of the complex in a matrix medium as well as the composition of the matrix material on the EC curves were also determined. 相似文献
20.
[Co(H2O)2Cl2(H2SeO3)2] (monoclinic, P21/c, Z = 2, a = 519.82(5), b = 1462.6(1), c = 643.09(7) pm, β = 92.51(1)°, Rall = 0.0583) was obtained from CoCl2 and H2SeO3 as purple plate–shaped single crystals. In the compound, the Co2+ ions are octahedrally coordinated by two Cl? ions, two H2O molecules, and two monodentate H2SeO3 molecules, leading to neutral complexes [Co(H2O)2Cl2(H2SeO3)2]. They are connected by hydrogen bonds involving both chlorine and oxygen atoms as acceptor atoms. 相似文献