Etude des spectres vibrationnels et des proprietes physico-chimiques du cyclotriphosphate mixte de nickel et de sodium hexahydrate,NiNa4(P3O9)2.6H2O

A study of the vibrational spectra and physico-chemical properties of nickel and sodium cyclotriphosphate hexahydrate, NiNa₄(P₃O₉)₂.6H₂O. We have studied the dehydration and the calcination under atmospheric pressure of cyclotriphosphate hexahydrate of nickel and sodium, NiNa₄(P₃O₉)₂.6H₂O, between 25 and 700°C by infrared spectrometry, X-ray diffraction, TGA and DTA thermal analyses. This study allows the identification and the crystallographic characterization of a new phase, NiNa₄(PO₃)₆, obtained between 350 and 450°C. NiNa₄(PO₃)₆ crystallizes in the triclinic system, P₋₁, with the following unit cell parameters a = 6.157(3)Å, b = 6.820(6)Å, c = 10.918(6)Å, α = 80.21(5)°, β= 97.80(9)°, γ = 113.49(3)°, V = 409.8 ų, Z = 1, M(19) = 25 and F(19) = 48 (0.0095; 42). The calcination of NiNa₄(PO₃)₆, between 500 and 600°C, leads to a mixture of long-chain polyphosphates NiNa(PO₃)₃ and NaPO₃. The kinetic characteristics of the dehydration of NiNa₄(P₃O₉)₂.6H₂O were determined and discussed. The vibrational spectrum of the title compound, NiNa₄(P₃O₉)₂.6H₂O, was interpreted in the domain of the stretching vibrations of the P₃O₉ rings, on the basis of its crystalline structure and in the light of the calculation of the normal IR frequencies of the P₃O₉ ring with D_3h symmetry.     

Dimethylammonium Trihydrogen 1-Hydroxyethane-1,1-diphosphonate

Dimethylammonium trihydrogen 1-hydroxyethane-1,1-diphosphonate (CH₃)₂NH₂(H₃L)·H₂O was prepared. Powder X-ray diffraction study showed that the polycrystalline product is single-phase. The thermal transformations of the compound were studied. The crystalline anhydrous salt was prepared by thermal dehydration of the monohydrate.     

Synthesis and crystal structure of bis (2-phenylethylammonium) dihydrogendimphosphate, [C6H5(CH2)2NH3]2H2P2O7

Chemical preparation, crystal structure and infrared absorption spectra are given for a new organic cation dihydrogendiphosphate. The new synthesized compound [C₆H₅(CH₂)₂NH₃]₂H₂P₂O₇; crystallized in the monoclinic system (P2_1/c space group) with Z = 4 and with the following unit-cell dimensions: a = 19.006(3); b = 10.718(2), c = 10.996(3) Å and β = 98.99(2) °. Its crystal structure was determined and refined down to R = 0,056 by using 3278 independent reflections. As in all atomic arrangements including acidic diphosphate groups; we can observe the formation of an infinite network of anions connected by strong H-bonds.     

Thermal behavior of the mixed composition xSb2O3–(1 − x)Bi2O3–6(NH4)2HPO4

The study of the system xSb₂O₃–(1 ? x)Bi₂O₃–6(NH₄)₂HPO₄ has been carried out to identify the phases and simulate the mechanisms of their formation, using the technique of thermal analysis in association with X-ray diffractometry. The main stages observed during thermal treatment of the samples include: (1) elimination of water and ammonia leading to the formation of (NH₄)₅P₃O₁₀; (2) reaction of the latter with M ₂ ^III O₃ and the formation of acidic polyphosphates M ₂ ^III H₂P₃O₁₀; (3) their dehydration with the formation of the polyphosphates M^III(PO₃)₃. Then Sb(PO₃)₃ decomposes giving SbPO₄ and P₂O₅. In the presence of excessive P₂O₅, two moles of Bi(PO₃)₃ condensate into oxophosphates Bi₂P₄O₁₃ and BiP₅O₁₄. The data of thermal analysis match with the composition of intermediate and final products. The hygroscopicity of the samples diminishes with growing bismuth content.     

Spirocyclic derivatives of nitronyl nitroxides in the design of heterospin CuII complexes manifesting spin transitions

A method was developed for the synthesis of a nitronyl nitroxide containing cyclopentane substituents in positions 4 and 5 of the imidazoline ring, viz., 2-(3-pyridyl)-4,5-bis(spiropentyl)-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl (L^CP). The reaction of Cu^II hexafluoroacetylacetonate with L^CP affords different products depending on the reaction conditions: mononuclear [Cu(hfac)₂(L^CP)₂], binuclear [Cu(hfac)₂L^CP]₂, tetranuclear {[Cu(hfac)₂]₄(L^CP)₂}, or chain polymer {[Cu(hfac)₂]₃(L^CP)₂} _n . Temperature changes induce structural transformations accompanied by a change in the spin state in exchange clusters in the solid [Cu(hfac)₂L^CP]₂ and {[Cu(hfac)₂]₄(L^CP)₂}.     

3-D Hydrogen bonded networks of three organically templated cadmium sulfates. Dehydration reactions and crystallization behavior

Three cadmium sulfates templated by either ethylenediamine, piperazine, or dabco, [NH₃(CH₂)₂NH₃][Cd(SO₄)₂(H₂O)₄] (1), (C₄H₁₂N₂)[Cd(H₂O)₆](SO₄)₂ (2), and (C₆H₁₄N₂)[Cd(H₂O)₆](SO₄)₂ (3), have been synthesized and crystallographically characterized. The structural studies show that they crystallize in P-1, P2₁/n, and P2₁/c space groups, respectively, and the solids present three different structure types. Thermal decomposition of all compounds depends not only on the structure type but also on the amino group involved in the structure. Three different thermal behaviors have been distinguished in the dehydration stage, which takes place in two, three, and one steps, in 1, 2, and 3, respectively. The temperature-dependent X-ray diffraction demonstrates that the anhydrous compound obtained by dehydration of 1 is a crystalline phase that is stable in a wide range of temperatures.     

Synthesis and Properties of Inorganic Triphosphate Crystal Hydrates

Abstract

The polycrystalline samples and single crystals of crystal hydrates of inorganic triphosphates with ring-like and chain-like anion structured were synthesized: lithium and sodium cyclotriphosphates, sodium and ammonium chain triphosphates, and double salts of chain triphosphoric acid (ammonium-potassium, ammonium-magnesium, ammonium-manganese). The crystallization field of the double salt of variable composition (NH₄,K)₃H₂P₃O₁₀ ·xH₂O (NH₄ :K=0.23–3.60; x=0.8–1.5) from aqueous solutions was established. Synthesis of Na₅P₃O₁₀ · 6D₂O crystals has been performed by the interaction of the high temperature form Na₅P₃O₁₀ (I) with D₂0. At 20°C and relative humidity RH < 70–80% the (NH₄) ₅P₃O₁₀·2H₂O crystals lose their transparency and generate different crystalline products depending on RH value: (NH₄)₅P₃O₁₀ at RH=0% or (NH₄)₅P_{3 10} · H₂O at RH=32%. The (NH₄) ₅P₃ O₁₀ · H₂O crystals are stable at RH < 60–70%, at RH=80% they absorb water and transform into (NH₄) ₅P₃O₁₀ · 2H₂0. In the latter case a characteristic picture is registered: on active sites situated on the (NH₄) ₅P₃O₁₀ · H₂O crystal face the appearance and epitaxial growth of (NH₄) ₅P₃O₁₀ · H₂O crystals is observed. For some single crystals the character of dehydration localization has been shown to correlate with space arrangement of phosphate groups in crystal structure. On the basis of the obtained results a model of dehydration front propagation in crystals has been suggested.     

Microwave assisted low temperature synthesis of sodium zirconium phosphate (NaZr<Subscript>2</Subscript>P<Subscript>3</Subscript>O<Subscript>12</Subscript>)

Sodium zirconium phosphate [NaZr₂P₃O₁₂], a potential ceramic matrix for fixation of high level nuclear waste, was synthesized by heating the mixture of sodium carbonate [Na₂CO₃], zirconyl nitrate hydrate [ZrO(NO₃)₂·5H₂O] and ammonium dihydrogen phosphate [NH₄H₂PO₄] in air, in a resistance heated furnace and a microwave heating system respectively in the temperature range 450 to 650°C. The mixture heated for 1 h in a resistance furnace at 450°C yielded a poorly crystalline NaZr₂P₃O₁₂ [NZP]. Increasing the temperature to 650°C produced a highly crystalline product. The same mixture heated in a microwave oven at 450°C for 1 h however, yielded the most crystalline NZP.In an alternate method, the mixture of sodium dihydrogen phosphate (NaH₂PO₄), zirconium dioxide (ZrO₂) and diammonium hydrogen phosphate [(NH₄)₂HPO₄] heated in resistance furnace at 650°C for the same period did not react in air. It also did not yield the pure product at 450°C when heated in microwave assembly for 1 h.The authors thank the Board of Research in Nuclear Sciences (BRNS) of the Department of Atomic Energy (DAE) for the financial support for this work under the project No. 2000/37/19/BRNS/1959 dtd09-02-02.     

Decomposition thermique et etude vibrationnelle de NiNa4(P3O9)2·6H2O

We have studied the dehydration and the calcination under atmospheric pressure of cyclotriphosphate tetrahydrate of nickel and sodium, NiNa₄(P₃O₉)₂·6H₂O, between 25 and 700°C by thermal analyses (TG, DTA) infrared spectrometry and X-ray diffraction. This study allows us the identification and the crystallographic characterization of a new phase, NiNa₄(PO₃)6, obtained between 350 and 450°C. NiNa₄(PO₃)₆ crystallizes in the triclinic system, P_–1, with the following unit cell parameters a=6.157(3) Å, b=6.820(6) Å, c=10.918(6) Å, =80.21(5)°, =97.80(9)°, =113.49(3)°, V=409.8 ų, Z=1, M(19)=25 and F(19)=48 (0.0095; 42). The calcination of NiNa₄(PO₃)₆, between 500 and 600°C, leads to a mixture of long-chain polyphosphates NiNa(PO₃)₃ and NaPO₃. The kinetic characteristics of the dehydration of NiNa₄(P₃O₉)₂·6H₂O were determined and discussed. The vibrational spectrum of the title compound, NiNa₄(P₃O₉)2·6H₂O, was interpreted in the domain of the stretching vibrations of the P₃O₉ rings, on the basis of its crystalline structure and in the light of the calculation of the normal IR frequencies of the P₃O₉ ring with D_3h symmetry.

This revised version was published online in November 2005 with corrections to the Cover Date.     

Equilibrium constant for coordinative polymerization of an o,o′-dihydroxyazobenzene derivative with Ni(II) ion in water

Equilibrium constant (K_CP) for coordinative polymerization is measured for the first time. Constant K_CP is defined as [L]_cp/[M][L], where [L]_cp represents the concentration of the ligand present in the coordination polymer. Plot of absorbance changes measured for 3, a water-soluble derivative of o,o′-dihydroxyazobenzene, against the concentration of Ni(II) ion indicates formation of a 1 : 1-type complex in water at pH 7.74 and 25°C when Ni (II) is added in excess of 3. The 1 : 1-type complex can be either Ni 3, the monomeric complex, or (Ni 3 )_n, the coordination polymer. The equilibrium constant for formation of the 1 : 1-type complex is estimated as 10^13.10 by using UO₂²⁺ ion as the competing metal ion. For the Ni(II) complex of an o,o′-dihydroxyazobenzene derivative attached to poly(ethylenimine), the formation constant is estimated as 10^5.36. Due to the structure of the polymer, possibility of coordinative polymerization is excluded for the polymer-based ligand. The much greater equilibrium constant for formation of the Ni(II) complex of 3, therefore, indicates formation of (Ni 3 )_n instead of Ni 3. The value of K_CP for (Ni 3 )_n shows that only 10⁻⁷% of the initially added 3 is left unpolymerized when Ni(II) is added in excess of 3 by 10⁻⁴ M. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 1825–1830, 1997     

Thermal decomposition of Cu(NO3)2·3H2O at reduced pressures

Thermolysis of Cu(NO₃)₂·3H₂O is studied by means of XRD analysis in situ and mass spectral analysis of the gas phase at P=1/10 Pa at low heating rate. It is shown that stage I of the dehydration (40-80 °C) results in the consecutive appearance of crystalline Cu(NO₃)₂·2.5H₂O and Cu(NO₃)·H₂O. Anhydrous Cu(NO₃)₂ formed during further dehydration at 80-110 °C is moderately sublimed at 120-150 °C. Dehydration is accompanied by thermohydrolysis, leading to the appearance of Cu₂(OH)₃NO₃ and gaseous H₂O, HNO₃, NO₂, and H₂O. The higher pressure in the system, the larger amount of thermohydrolysis products is observed. The formation of the crystalline intermediate CuO_x(NO₃)_y was observed by diffraction methods. Final product of thermolysis (CuO) is formed at 200-250 °C.     

Degradation thermique et etude vibrationnelle de MII(NH4)4(P3O9)2x4H2O(M II=Cu2+, Ni2+, Co2+)

We have studied the thermal behaviour under atmospheric pressure of isotypic tetrahydrate cyclotriphosphates M^II(NH₄)₄(P₃O₉)₂x4H₂O (M ^II=Cu, Ni and Co), between 25 and 1400°C, by X-ray diffraction, thermal analyses (TG and DTA) and infrared spectrometry. This study shows that the series of the compounds M^II(NH₄)₄(P₃O₉)₂x4H₂O (M ^II=Cu, Ni and Co) after elimination of water, in two different stages, and ammonia leads, at 400°C to cyclotetraphosphate M₂ ^IIP₄O₁₂ crystallized and to a thermal residue with a formula H₄P₄O₁₂ which undergoes under a thermal degradation by evolving water and pentoxide phosphorus. The kinetic characteristics of the dehydration and elimination of ammonia have been determinated. The vibrational spectra of Cu(NH₄)₄(P₃O₉)₂x4H₂O were examined and interpreted, in the domain of the valency frequencies, on the basis of the crystalline structure of its isotypic compound Co(NH₄)₄(P₃O₉)₂x4H₂O whose cycle has the site symmetry C₁, of our results of the calculation of the IR frequencies and the successive isotopic substitutions of the equivalent atoms (3P, 3Oi and 6Oe belonging to the P₃Oi₃Oe₆ ring) of the P₃O₉ ³⁻ cycle with high symmetry D_3h. This revised version was published online in August 2006 with corrections to the Cover Date.     

Synthesis and characterization of block poly(ester‐ether‐urethane)s from bacterial poly(3‐hydroxybutyrate) oligomers

Telechelic hydroxylated poly(3‐hydroxybutyrate) (PHB‐diol) oligomers have been successfully synthesized in 90–95% yield from high molar mass PHB by tin‐catalyzed alcoholysis with different diols (mainly 1,4‐butanediol) in diglyme. The PHB‐diol oligomers structure was studied by nuclear magnetic resonance, Fourier transformed infrared spectroscopy MALDI‐ToF MS, and size exclusion chromatography, whereas their crystalline structures, thermal properties and thermal stability were analyzed by wide angle X‐ray scattering, DSC, and thermogravimetric analyses. The kinetic of the alcoholysis was studied and the influence of (i) the catalyst amount, (ii) the diol amount, (iii) the reaction temperature, and (iv) the diol chain length on the molar mass was discussed. The influence of the PHB‐diol molar mass on the thermal stability, the thermal properties and optical properties was investigated. Then, tin‐catalyzed poly(ester‐ether‐urethane)s (PEEU) of M_n = 15,000–20,000 g/mol were synthesized in 1,2‐dichloroethane from PHB‐diol oligomers (P_ester) with modified 4,4'‐MDI and different polyether‐diols (P_ether) (PEG‐2000, PEG‐4000, and PPG‐PEG‐PPG). The influence of the PHB‐diol chain length, the P_ether/P_ester ratio, the polyether segment nature and the PEG chain length on the thermal properties and crystalline structures of PEEUs was particularly discussed. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 1949–1961     

Synthesis of the Cu2-x Mgx P4 O12 and Ni2-x Mgx P4 O12

Abstract

Some binary cyclo-tetraphosphates have been synthetized by means of thermal dehydration of the starting binary dihydrogenphosphate. The mechanism of dehydration and condensation reactions in dependence on various special conditions of thermal preparation (temp. rate, water vapour pressure, using nuclei) has been studied. The methods of TA at quasi-isothermal and quasi-isobaric conditions with combination of calcination experiments have been used for these purposes. The reaction products obtained were analyzed by chromatography, IR-spectrosco-py, X-ray diffraction analysis, electron microscopy and AAS. The course, the rate and the yields of the condensation reactions of formation of the main products considered Cu_2-xMg_xP₄O₁₂ and Ni_2-xMg_XP₄)₁₂, have been investigated. These coloured products (green or yellow-green) crystallize in the monoclinic system, C2c group (where x ε (0; 2)). Their structural parameters have the values for Cu_2-xMg_xP₄O₁₂ or Ni_2-xMg_xP₄O₁₂ (X = 2 to x = 0) : a = 11.749(5) to 12.546(7) or 11.644(5) Å, b = 8.278(4) to 8.092(5) or 8.236(4) Å, c = 9.905(4) to 9.565(5) Or 9.813 Å and β = 118.92(2)° to 118.63(3)° or 118.53(2)°, respectively.     

Thermoanalytical studies of natural potassium, sodium and ammonium alunites

Dynamic and controlled rate thermal analysis (CRTA) has been used to characterise alunites of formula [M(Al)₃(SO₄)₂(OH)₆] where M⁺ is the cations K⁺, Na⁺ or NH₄ ⁺. Thermal decomposition occurs in a series of steps: (a) dehydration, (b) well-defined dehydroxylation and (c) desulphation. CRTA offers a better resolution and a more detailed interpretation of water formation processes via approaching equilibrium conditions of decomposition through the elimination of the slow transfer of heat to the sample as a controlling parameter on the process of decomposition. Constant-rate decomposition processes of water formation reveal the subtle nature of dehydration and dehydroxylation.     

Synthesis and thermal decomposition of some rare earth tetramethylammonium double sulphates

When reaction mixtures of rare earth(III) sulphates and tetramethylammonium sulphate in molar ratios of from 1∶4 to 1∶12 were evaporated at ambient temperature and the concentrated reaction mixture was treated with ethanol, double sulphates with general empirical formula (CH₃)₄NLn(SO₄)₂·2H₂O (Ln=Ho?Lu and Y) were obtained as reaction products. The crystalline products were identified by quantitative analysis, X-ray powder diffraction patterns and TG, DTG and DTA analysis. They were found to be isostructural. Their thermal decomposition took place in three stages. The temperature range of the dehydration mainly decreased from Ho to Lu. The thermal decomposition in the second and third stages occurred with many thermal events. As final product, Ln₂O(SO₄)₂ was obtained.     

Hg4OF6, das erste Quecksilberoxidfluorid

Hg₄OF₆, the First Mercury Oxide Fluoride Hg₄OF₆ was observed at the first time as a product of the thermal decomposition of (O₂)₂Hg₂F(SbF₆)₅. The pure compound has been obtained via solid state reaction of HgO and HgF₂ as a vermilion, crystalline powder. It crystallises hexagonally in the Ba₄OCl₆ type of structure (P6₃mc (No. 186), a = 774.57(1), c = 600.75(1) pm, Z = 2, Rietveld profile fitting, R_P = 6.17 %, R_wP = 8.00 %).     

Thermal decomposition of rare earth element enanthates

The conditions of formation of Y, La and lanthanide (from Ce(III) to Lu) enanthates were worked out, their composition and their solubilities in water at 291 K were determined, and the conditions of their thermal decomposition were studied. They were prepared as crystalline solids with general formula Ln(C₇H₁₃O₂)₃·nH₂O, wheren=2–10. On heating, they decompose in two or three steps. They first lose some water molecules and then decompose to the oxides directly (salts of Y and heavy lanthanides) or via the intermediate formation of Ln₂O₂CO₃ (salts of La, Pr, Nd, Sm and Eu). Only yttrium enanthate dihydrate loses 2 water molecules on heating to form an anhydrous complex, which decomposes directly to Y₂O₃. The temperatures of dehydration are similar for all complexes (323–343 K), while the temperatures of oxide formation vary irregularly from 823 K for CeO₂ to 1078 K for La₂O₃.     

Synthesis and study of sodium triuranate Na<Subscript>2</Subscript>(UO<Subscript>2</Subscript>)<Subscript>3</Subscript>O<Subscript>3</Subscript>(OH)<Subscript>2</Subscript>

Sodium triuranate Na₂(UO₂)₃O₃(OH)₂ was synthesized by the reaction between aqueous uranyl acetate solution and aqueous sodium nitrate solution under hydrothermal conditions at 200°C. The composition and structure of the synthesized compound were determined, and its dehydration and thermal decomposition were studied, by chemical analysis, X-ray diffraction, IR spectroscopy, and thermal analysis.     

Synthesis,characterisation and thermal decomposition of double sulfate

Upon evaporation at room temperature of an aqueous mixture containing Al(III) sulfate and trishydroxymethyl-ammoniummethane sulfate in a molar ratio 1:2, double sulfate as crystalline product was obtained. The stoichiometry of the obtained compound was determined by means of elemental and TG analysis. For identification, IR-spectra and X-ray powder diffraction patterns were done. It was found that the general formula of the obtained compound is Al(HOCH₂)₃CNH₃(SO₄)₂·₆H₂O. as revealed by TG, DTG and DTA analysis, the dehydration of the AL-compound takes place in one step which points out that the six water molecules are bonded in the same way. The thermal decomposition of the anhydrous compound starts at about 260°C and is very complex. This process takes place in many steps which are not well resolved. The pathway of the thermal decomposition is also supposed. This revised version was published online in July 2006 with corrections to the Cover Date.