Non-isothermal Decomposition Kinetics of Complexes [ Sm(m-MBA)3 phen]2 and [ Sm(o-MOBA)3 phen] 2·2H2O

Introduction In recent years, there has been considerable interest in complexes formed by lanthanide cations and various benzoate derivatives[1-4], due to their potential application in areas, such as extraction, separation,germicide preparation, catalysis, luminescence, and functional material preparation[5].     

Nonisothermal Kinetice of Dehydration Process of [Sm(m-CIBA)3phen]2·2H2O and[Sm(p-CIBA)3phen]2·2H2O

Compounds[Sm(m-CIBA)3phen]2·2H2O and[Sm(p-ClBA)3phen]2·2H2O(m-ClBA=m-chlorobenzoate,PClBA=p-chlorobenzoate,phen=1,10-phenanthroline)were prepared.The dehydration processes and kinetics of these compounds were studied from the analysis of the DSC curves using a method of processing the data of thermal analysis kinetics.The Arrhenius equation for the dehydration process can be expressed as lnk=38.65-243.90x103|RT for and△S≠ of dehydration reaction for the title compounds are determined,respectively.     

Thermal decomposition kinetics and reversible hydration study of the Li2Zn(HPO4)2·H2O

The dilithium zinc hydrogen phosphate monohydrate (Li₂Zn(HPO₄)₂·H₂O) was synthesized at the ambient temperature by using zinc acetyl acetonate monohydrate, phosphoric acid and lithium hydroxide monohydrate. The thermal stability of the Li₂Zn(HPO₄)₂·H₂O was studied by non-isothermal kinetic method (Ozawa and Kissinger) from the differential scanning calorimetric (DSC) data. The studied hydrate undergoes two endothermic thermal transformations, which the first transformation is due to the release of water molecule of crystallization and the second one is due to the release of water of constituent from HPO₄^2? anions and transforms to P₂O₇^4?. The activation energies (E_a) calculated for the dehydration step and decomposition step of the Li₂Zn(HPO₄)₂·H₂O from different methods were found to be consistent. The dehydration and rehydration processes of the synthesized compound were investigated and found that the water of crystallization can be removed and rehydrated without the disrupting the structure of the material, provided it is not heated beyond 200 °C. The dehydration and rehydration processes of the synthesized Li₂Zn(HPO₄)₂·H₂O exhibits similar property to the zeolite.     

Thermal decomposition of lutetium nitrate trihydrate Lu(NO3)3·3H2O

Journal of Thermal Analysis and Calorimetry - The thermal decomposition of lutetium nitrate starts with essentially a process of dehydration of the initial monomer Lu(NO3)3·3H2O with further...     

Nonisothermal Kinetics of Dehydration Process of [Sm（m-CIBA）3phen]2·2H2O and [Sm（p-CIBA）3phen]2·2H2O

Compounds [Sm（m-CIBA）3phen]2.2H20 and [Sm（p-CIBA）3phen]2·2H20（m-CIBA=m-chlorobenzoate, pClBA=p-chlorobenzoate, phen=l,10-phenanthroline） were prepared. The dehydration processes and kinetics of these compounds were studied from the analysis of the DSC curves using a method of processing the data of thermal analysis kinetics. The Arrhenius equation for the dehydration process can be expressed as lnk=-38.65-243.90×l0^3/RT for [Sm（m-CIBA）3phen]2·2H2O, and lnk=38.70-172.22×103/RT for [Sm（p-CIBA）3phen]2·2H2O. The values of △H^1, △G^1, and △S^1 of dehydration reaction for the title comnonnds are determined respectively.     

The solid-state thermal decomposition of Sr3[La(C2O4)3(H2O)2]2·11H2O

Strontium(II)diaquatris(oxalato)lanthanate(III)unidecahydrate, Sr₃[La(C₂O₄)₃(H₂O)₂]₂·11H₂O, has been synthesized and characterized by elemental, IR and electronic spectral studies. Thermal studies (TG, DTG and DTA) in air showed that all the crystal and coordinated water molecules are removed at ca. 225 °C. The final end product at 1,000 °C was shown to be a mixture of mainly SrCO₃, Sr₃La₄O₉ and La₂Sr₂O₅ along with oxides and carbides of both the metal, through the formation of an intermediate mixture of likely SrC₂O₄ and La₂(C₂O₄)_2.8 at 282 °C, and SrCO₃ and La₂O(CO₃)₂ at 540 °C. The multi-step dehydration and decomposition of the compound has been explored from the DSC study in nitrogen up to 670 °C, and the evaluated kinetic parameters are discussed.     

Non-isothermal Decomposition Kinetics of Complexes[Sm（m-MBA）3 phen] 2 and [Sm（o-MOBA）3 phen]2 ·2H2O

Introduction In recent years,there has been considerable interest in complexes formed by lanthanide cations and various benzoate derivatives[1-4],due to their potential application in areas,such as extraction,separation, germicide preparation,catalysis,luminescence,and functional material preparation[5].As a continuation of the study on lanthanide carboxylate[6-13],samarium     

On the thermal decomposition of [Fe2NiO(CH3COO)6(H2O)3]·2H2O

The heteronuclear-oxoacetate with the composition [Fe₂NiO(CH₂COO)₆(H₂O)₃]·2H₂O decomposed on heating, forming nickel ferrite NiFe₂O₄ and (depending on the decomposition conditions) in part other solid phases. H₂O, CH₃COOH, acetone and CO₂ were also formed in the decomposition. A reaction scheme is given for the decomposition. The products were porous powders with grain diameters between 3 and 10m. On increase of the temperature of decomposition from 300 to 800 C, the BET surface area and the surface area of the pores decreased, but only a small alteration in grain size was observed. As a result of thermal treatment in the temperature region abone 800C, larger aggregates of grains were formed in sintering processes.

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Zusammenfassung Heteronukleare-Oxoazetate der Zusammensetzung [Fe₂NiO(CH₃COO)₆(H₂O)₃]·2H₂O werden durch Erhitzen zersetzt, wobei Nickelferrite NiFe₂O₄ und — in AbhÄngigkeit von den Bedingungen der Zersetzung — mit einem Teil anderer fester Phasen gebildet wird. In der Zersetzungsreaktion werden auch H₂O, CH₃COOH, Azeton und CO₂ gebildet. Es wird ein Reaktionsschema für die Zersetzung angegeben. Die Produkte sind poröse Pulver mit einem Korndurchmesser zwischen 3 und 10 m. Wird die Zersetzungstemperatur von 300 auf 800C erhöht, nimmt die BET-OberflÄche und die PorenoberflÄche ab, wobei sich die Korngrö\e aber nur wenig verÄndert. Im Ergebnis der WÄrmebehandlung im Temperaturbereich oberhalb 800C werden durch Sinterprozesse grö\ere Partikelaggregate gebildet.

     

Thermal dehydration and decomposition of FeCl3·xH2O

Thermal dehydration and decomposition characteristics of Fe(III) chloride hydrate have been studied by both isothermal and non-isothermal methods. After the initial melting at 35–40°C both dehydration and decomposition of the salt proceed simultaneously at temperature above 100°C. At 250–300°C a stable hydrated Fe(OH)₂Cl is formed representing the first plateau region in the TG curve. Around 400°C, a second plateau is observed corresponding to the formation of mostly Fe₂O₃ which however retains some OH groups and Cl^– ions. However, these temperature ranges vary with the TA equipments used. Chemical analysis of the products of decomposition at temperatures above 140°C also gives evidence for the formation of FeOCl which on hydrolysis in water gives FeCl₃ in solution. The FT-IR spectra suggest the presence of structural OH groups even for samples calcined at 300–400°C. The XRD patterns of the products of decomposition in the temperature range 160–400°C indicate the presence of -FeOOH, some unidentified basic chlorides and -Fe₂O₃.The authors wish to thank the Director, R. R. L. Bhubaneswar for his kind permission to publish this paper. One of the authors (SKM) is grateful to the Council of Scientific and Industrial Research (CSIR), New Delhi for the award of a fellowship.     

Synthesis, properties, and thermal decomposition of compounds [Co(En)3][Fe(CN)6] · 2H2O and [Co(En)3]4[Fe(CN)6]3 · 15H2O

Binary complex salts, [Co(En)₃][Fe(CN)6] · 2H₂O and [Co(En)₃]₄[Fe(CN)₆]₃ · 15H₂O, are synthesized. The properties of the salts and their thermolysis in air, dihydrogen, and argon are studied. Oxides of the central ions of the binary complex salts are found to be the thermolysis products in an oxidative atmosphere. Solid solutions (intermetallic compounds) CoFe are the thermolysis products in the reductive atmosphere, whereas intermetallides containing considerable amounts of C and N and an impurity of Co and Fe oxides are the thermolysis products in an inert atmosphere. Gaseous thermolysis products in dihydrogen and argon are NH₃, hydrocarbons, and ethylenediamine.     

Thermal decomposition and kinetic data of Cd(BF4)2·6H2O

The thermal dehydration and decomposition of Cd(BF₄)₂·6H₂O were studied by means of DTA, TG, DSC and X-ray diffraction methods and the end products of the thermal decomposition were identified. The results of thermal analysis show that the compound is fused first, then it is dehydrated until Cd(BF₄)₂·3H₂O is obtained, which has not been described in the literature so far. The enthalpy of phase transition is H _ph.tr.=115.6 kJ mol^–1 Separation of the compound is difficult since it is highly hygroscopic. Then, dehydration and decomposition take place simultaneously until CdF₂ is obtained which is proved by X-ray diffraction. On further increasing the temperature, CdF₂ is oxidized to CdO and the characteristic curve assumes a linear character.Based on TG data, kinetic analyses were carried out separately for both parts of the curve: first until formation of the trihydrate and then — until formation of CdF₂. The formal kinetic parameters are as follows:for the first phase:E ^*=45.3 kJ mol^–1; rate equationF=^2/3; correlation coefficient 0.9858 for the second phase:E ^*=230.1 kJ mol^–1; rate equationF=(1–)^2/3[1-(1–)^1/3]^–1; correlation coefficient 0.9982.     

Structure of Coordination Polymer,[Zn (bipy) (H2O) 3SO4] · 2H2O (bipy = 4,4'-bipyridine)

The crystal of the title compound (C10H18N2O9SZn Mr= 407. 69) belongs to the hexagonal system, space group P65 with cell parameters: a= 11. 411(2), c=20. 908(4) A, V=2357.7(7)A 3, Z=6, Dc=1. 723g/cm3, F(000)=1260,μ(MoKα) =1. 743mm-1. The final R and wR factors are 0. 072 and 0. 178 respectively for 1335 observed reflections. In the structure, zinc ions are bridged by 4,4'-bipyridine to form infinite chains. The sheets containing parallel chains stack along a 65 screw axis to give a helical staircase motif. The helical structure is mainly controlled by the hydrogen bonds.     

Thermal decomposition of RE(C2H5CO2)3·H2O (RE = Dy,Tb, Gd,Eu and Sm)

The thermal decomposition of Dy(III), Tb(III), Gd(III), Eu(III), and Sm(III) propionate monohydrates was studied in argon by means of simultaneous differential thermal analysis and thermogravimetry, infrared-spectroscopy, X-ray diffraction, and optical microscopy. After dehydration, which takes place below 120 °C, all salts decompose into dioxycarbonates with simultaneous release of CO₂ and C₂H₅COC₂H₅ (3-pentanone) between 250 and 460 °C. However, whereas the anhydrous Dy-, Tb-, and Gd-propionates appear to transform into RE₂O₂CO₃ (rare earth [RE] = Dy, Tb, Gd) in a single step, an intermediate stage involving a RE₂O(C₂H₅CO₂)₄ composition was evidenced in the case of the Eu- and Sm-propionates. For all compounds, further decomposition of RE₂O₂CO₃ into the corresponding sesquioxides (RE₂O₃) is accompanied by the release of CO₂. The thermal decomposition of Dy- and Tb-propionates occurs entirely in the solid state. In contrast the dehydrated Gd-, Eu-, and Sm-propionates melt at increasingly higher temperatures. Evidence for recrystallization was found in conjunction with the onset of decomposition of these three propionates.     

Syntheses and structural determination of eight-coordinate Na[YbIII(Cydta)(H2O)2] · 5H2O and [YbIII(Hegta)] · 2H2O complexes

Na[Yb^III(Cydta)(H₂O)₂] · 5H₂O (1) (H₄Cydta = trans-1,2-cyclohexanediamine-N,N,N′,N′-tetraacetic acid) and [Yb^III(Hegta)] · 2H₂O (2) (H₄egta = ethyleneglycol-bis-(2-aminoethylether)-N,N,N′,N′-tetraacetic acid) were prepared and their composition and structures were determined by elemental analyses and single-crystal X-ray diffraction techniques. Complex 1 crystallized in the triclinic crystal system with space group P 1; the Yb^III is eight-coordinate by a hexadentate Cydta and two water molecules. Complex 2 is a protonated egta complex, crystallized in the monoclinic crystal system with space group P 2 ₁ /c; Yb^III is coordinated only by the octadentate Hegta ligand. Both these complexes adopt a pseudo-square antiprismatic conformation.     

Studies on the non-isothermal kinetics of the thermal decomposition of [Cu(NBOCTB)][Cu(NO3)4]· H2O

The thermal decomposition process of the complex [Cu(NBOCTB)][Cu(NO₃)₄] H₂O has been studied by TG and DTG technique, and possible intermediates of the thermal decomposition have also been conjectured from the TG and DTG curves. The results suggest that the decomposition of the complex involves five steps: The non-isothermal kinetics of steps 1, 2 and 3 have been studied by means of the Achar and Coats-Redfern method based on TG and DTG curves. Step 1 is a Coring and Growth mechanism (n= 1), its kinetic equation may be expressed as: d/dt=Ae^–E/RT(1–). Steps 2 and 3 are both two order chemical reaction mechanisms, their kinetic equations can be expressed as: d/dt=Ae^–E/RT(1–)².This project was supported by the National Natural Science Youth Fundation of China.     

Syntheses and structural determination of the nine-coordinate rare earth metal complexes: [TbIII(Eg3a)(H2O)2] · 4.5H2O and K[TbIII(Edta)(H2O)3] · 5H2O

Two title complexes, [Tb^III(Eg3a)(H₂O)₂] · 4.5H₂O (I) (H₃Eg3a = 3-carboxymethyl-6, 9-dioxa-3,12-diazatetradecanedioic acid) and K[Tb^III(Edta)(H₂O)₃] · 5H₂O(II) (H₄Edta = ethylenediamine-N,N,N′,N′-tetraaceti acid), were prepared and characterized by FT-IR, elemental analyses, TGA-DTA-DTG, and single-crystal X-ray diffraction technique. For I, the Tb³⁺ ion is nine-coordinated by an Eg3a ligand and two coordination water molecules, yielding a monocapped square-antiprismatic (MCSAP) conformation. Complex I crystallizes in the monoclinic system with P2₁/c space group. The crystal data are as follows: a = 9.237(3), b = 10.018(3), c = 23.580(7) Å, β = 99.021(5)°, V = 2155.2(11) ų, Z = 4, ρ = 1.822 Mg m^?3, μ = 3.353 mm^?1, F(000) = 1180, R ₁ = 0.0445 and wR ₂ = 0.1034 for 4262 observed reflections with I ≥ 2σ(I). For II, the Tb³⁺ ion is nine-coordinated by an Edta ligand and three coordinate water molecules also yielding a MCSAP conformation. Complex II crystallizes in the orthorhombic system with Fdd2 space group. The crystal data are as follows: a = 19.373(5), b = 35.429(10), c = 12.114(3) Å, V = 8315(4) ų, Z = 16, ρ = 2.014 Mg m^?3, μ = 2.014 mm^?1, F(000) = 5024, R ₁ = 0.0224 and wR ₂ = 0.0557 for 3189 observed reflections with I ≥ 2σ(I). The potassium cations bridge the coordination spheres yielding many infinite long 1-D zigzag-type chains. The molecular structure of I is more stable than that of II. According to thermal analyses, the collapsing temperatures of crystal structure are 314°C for I and 348°C for II, which indicates that the crystal structure of II is more stable.     

Syntheses and structures of nine-coordinate NH4[HoIII(Edta)(H2O)3] · 1.5H2O, (NH4)4[Ho 2 III (Dtpa)2] · 9H2O, and (NH4)3[HoIII(Ttha)] · 5H2O complexes

The three title complexes, NH₄[Ho^III(Edta)(H₂O)₃] · 1.5H₂O (I) (H₄Edta = ethylenedianine-N,N,N′,N′-tetraacetic acid), (NH₄)₄[Ho ₂ ^III (Dtpa)₂] · 9H₂O (II) (H₅Dtpa = diethylenetriamine-N,N,N′,N″,N″-entaacetic acid), and (NH₄)₃[Ho^III(Ttha)] · 5H₂O (III) (H₆ Ttha = triethylenetetramine-N,N,N′,N″,N?,N?-hexaacetic acid), have been prepared and characterized by FT-IR, elemental analyses, and single-crystal X-ray diffraction technique. Complex I has a nine-coordinate mononuclear structure with distorted monocapped square antiprismatic conformation and its crystal structure belongs to orthorhombic system and Fdd2 space group. The crystal data are as follows: a = 19.343(9), b = 35.125(17), c = 12.364(6) Å, V = 8400(7) ų, Z = 16, M = 552.26, ρ_calcd = 1.747 g cm^?3 μ = 3.828 mm^?1, and F(000) = 4368. Complex II has a binuclear nine-coordinate pseudomonocapped square antiprismatic conformation and its crystal structure belongs to triclinic system and space P1 group. The crystal data are as follows: a = 9.7637(16), b = 9.9722(16), c = 12.945(2) Å, α= 85.853(2)°, β = 77. 140(2)°, γ = 77.140(2)°, V = 1198.4(3) ų, Z = 1, M = 1340.80, ρ_calcd = 1.858 g cm^?3, μ = 3.380 mm^?1, and F(000) = 674. As for complex III, it also has nine-coordinate mononuclear structure with distorted tricapped trigonal prism and its crystal structure belongs to monoclinic system andP2₁/c space group. The crystal data are as follows: a = 10.349(3), b = 12.760(4), c = 23.142(7) Å, β = 91.020(6)°, V = 3055.6(16) ų, Z = 2, M = 797.55, ρ_calcd = 1.734 g cm^?3, μ = 2.674 mm^?1, and F(000) = 1624. The results showed that although the ligands are different from one another in the shape and the numbers of coordination atoms, they all have nine-coordinate structures. However, one of them has binuclear structure and the other two have mononuclear structures because of the difference of the ligands.     

The layer crystal structure of [In2(C2O4)3(H2O)3]·7H2O and microstructure of nanocrystalline In2O3 obtained from thermal decomposition

A new indium oxalate, [In₂(C₂O₄)₃(H₂O)₃]·7H₂O, with a layered structure has been synthesised from precipitation methods at room temperature. It crystallises with a monoclinic symmetry, space group P2₁/c (No. 14), a=8.7456(1) Å, b=11.1479(2) Å, c=21.9376(4) Å, β=112.1(1)°, V=1979.98(6) ų and Z=4. The structure is built from neutral [In₂(C₂O₄)₃(H₂O)₃] corrugated layers, between which water molecules are intercalated. The layers are built from chains with two different sequences of indium atoms and bichelating oxalate groups. Two independent indium atoms are present in the structure with two coordination polyhedra, i.e., InO₈ as a distorted square-based antiprism and InO₇ as a nearly regular pentagonal-based bipyramid. The thermal decomposition has been studied in situ by temperature dependent X-ray diffraction and thermogravimety. The final product is nanocrystalline indium oxide. The microstructure of the oxide has been characterised with both the Voigt/Langford method based on the integral breadth and the whole pattern fitting approach. The size of the isotropic crystallites increases from 322 to 924 Å, while microstrains decrease, in the annealing temperature range 500–750 °C.     

Synthesis and Structure of anti-Configuration Complex [Cu(tssb)2]·2[(H3O)Cl]·4H2O

The title complex [Cu(tssb)2]·2[(H3O)Cl]·4H2O (C18H34Cl2CuN2O14S2) (tssb = taurine salicylaldehyde Schiff base) has been synthesized by the reaction of taurine salicylaldehyde Schiff base (tssb) and copper acetate in water-ethanol. Its single-crystal structure was determined by X-ray diffraction method. The crystal structure belongs to triclinic, space group P with a = 0.7407(1), b = 1.3329(3), c = 1.5736(3)nm, α = 103.800(4), β = 95.030(4), γ = 104.416(4)°, Mr = 701.06, V = 1.4433(5) nm3, Z = 2, Dc = 1.613 g/cm3, μ = 1.153 mm-1 and F(000) = 726. The compound is an infinitely expanding three-dimensional network connected with hydrogen bonds. The Cu(Ⅱ) atom is coordinated by two nitrogen and two oxygen atoms to form a distorted planar coordination compound which adopts anti-configuration because two sulfonic acid groups are positioned diagonally on a plane.