Thermal decomposition of the [Co(NH3)6]Cl3, Co[(NH3)4Cl2]Cl,K3[Fe(C2O4)3]3H2O and Fe(CH3COO)3 in argon and air atmosphere

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.

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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.

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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.     

Thermal decomposition of [Co(NH3)5Cl]Cl2

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.     

Thermal decomposition of hexamminechromium (III) chloride

In this paper the results of comparative thermal analysis TG-DTG-DTA-DSC for the thermal decomposition process of [Cr(NH₃)₆]Cl₃ in air atmosphere are given. The kinetics and mechanism of this complex thermal decomposition, process enthalpy as the changes of specific thermal capacity of solid products reaction with temperature were determined.

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Zusammenfassung Es werden die Ergebnisse einer vergleichenden Thermoanalyse TG-DTG-DTA-DSC des thermischen Zersetzungsprozesses von [Cr(NH₃)₆]Cl₃ in Luft dargelegt. Weiterhin wurde die Kinetik und der Mechanismus dieses komplexen thermischen Zersetzungsprozesses, die Enthalpie des Vorganges sowie die temperaturbedingten Änderung der WÄrmekapazitÄt dieser Festkörperreaktion bestimmt.

     

Powder X-ray diffraction study of the double complexes [M(NH3)5Cl][M"Cl4] as precursors of metal powders (M = Ir,Rh, Co; M" = Pt,Pd)

According to the results of powder X-ray diffraction study of the complex salts of composition [M(NH₃)₅Cl][M"Cl₄] (M = Ir, Rh, or Co and M" = Pt or Pd), the anhydrous salts crystallize in the orthorhombic system (space group Pnma) and are isostructural to the [Ir(NH₃)₅Cl][PtCl₄] complex studied previously. The unit cell parameters of the resulting salts were refined. The metal powders, which were obtained by thermal decomposition of these salts under an atmosphere of hydrogen, were studied by powder X-ray analysis.     

Darstellung und Kristallstruktur von (NH4)2[V(NH3)Cl5]. Die Kristallchemie der Salze (NH4)2[V(NH3)Cl5], [Rh(NH3)5Cl]Cl2 und M2VXCl5 mit M = K,NH4, Rb,Cs und X = Cl,O

Preparation and Crystal Structure of (NH₄)₂[V(NH₃)Cl₅]. The Crystal Chemistry of the Compounds (NH₄)₂[V(NH₃)Cl₅], [Rh(NH₃)₅Cl]Cl₂, and M₂VXCl₅ with M = K, NH₄, Rb, Cs and X ? Cl, O (NH₄)₂[V(NH₃)Cl₅] crystallizes like [Rh(NH₃)₅Cl]Cl₂ in the orthorhombic space group Pnma with Z = 4. The compounds are built up by isolated NH₄⁺ or Cl^? and complex MX₅Y ions. The following distances have been observed: V? N: 213.8, V? Cl: 235.8–239.1, Rh? N: 207.1–208.5, Rh? Cl: 235.5 pm. Both structures differ from the K₂PtCl₆ type mainly in the ordering of the MX₅Y polyhedra. The compounds M₂VCl₆ and M₂VOCl₅ with M = K, NH₄, Rb, and Cs crystallize with exception of the orthorhombic K₂VOCl₅ in the K₂PtCl₆ type. The ordering of the MX₅Y polyhedra in the compounds (NH₄)₂[V(NH₃)Cl₅], [Rh(NH₃)₅Cl]Cl₂ and K₂VOCl₅ enables a closer packing.     

Studies on the solid state reactions of coordination conpounds. XLVIII. The effect of KSCN on the thermal decomposition of cobalt(III)-ammine complexes

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.     

Crystal Structure of [M(NH3)5Cl]2[IrCl6]Cl2 (M = Co, Rh, Ir) Binary Complex Salts

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.     

Ozone analysis by chemiluminescence measurement

Summary Ozone concentrations in ambient air can be determined by measuring light emitted by reaction with the chemiluminescent dye Rhodamine B. The stability of the light emission is increased by protecting the dye by another compound, which reacts with ozone more easily, i.e. gallic acid.The stability of the chemiluminescent surface is also increased by an intermittent sampling procedure. This is accomplished by means of a threeway valve allowing each minute the introduction of ozonized air for about 15 sec in the reaction chamber, followed by the introduction of ozone-free air for about 45 sec. In this way also a check on the stability of the zero-point of the detecting system is obtained.The method is highly selective. No interferences of NO₂, Cl₂, SO₂, H₂S, NH₃, HCl, H₂O₂ and HF have been observed at concentrations up to 2 ppm. The sensitivity of the chemiluminescent surface is decreased by adsorbed moisture. The moisture problem can be eliminated by coating the surface with a hydrophobic compound and by controlling the relative humidity of the ozone-free air, introduced into the reaction chamber between the actual ozone measurements.

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Ozonanalyse, durch Chemiluminescenzmessung

Zusammenfassung Ozon kann in atmosphÄrischer Luft auf Grund der Chemiluminescenzreaktion mit Rhodamin B bestimmt werden. Dabei wird die StabilitÄt der Lichtemission durch Zusatz von GallussÄure, die leichter mit Ozon reagiert, stabilisiert. Die StabilitÄt der leuchtenden FlÄche wird au\erdem durch ein intermittierendes Probenahmeverfahren verbessert. Hierbei wird je Minute 15 sec lang ozonhaltige Luft und 45 sec lang ozonfreie Luft in die Reaktionskammer geleitet. Dadurch wird zugleich eine Kontrolle des Nullpunktes ermöglicht. Das Verfahren ist sehr selektiv. NO₂, Cl₂, SO₂, H₂S, NH₃, HCl, H₂O₂ und HF verursachen bis zu 2 ppm keine Störungen. Da adsorbierte Feuchtigkeit die Empfindlichkeit der leuchtenden FlÄche beeintrÄchtigt, wird diese mit einer hydrophoben Schutzschicht überzogen sowie die relative Feuchtigkeit der ozonfreien Luft, die zwischen den Messungen durch die Kammer geleitet wird, unter Kontrolle gehalten.

     

Initial state and transition state contributions to reactivity in mercury(II)-catalysed aquation of thetrans-[Rh(en)2Cl2]+, [Cr(NH3)5Cl]2+, andcis-[Cr(NH3)4(OH2)Cl]2+ cations in binary aqueous solvent mixtures

Summary Rate constants are reported for mercury(II)-catalysed aquation of thetrans-[Rh(en)₂Cl₂]⁺, [Cr(NH₃)₅Cl]²⁺, andcis-[Cr(NH₃)₄(OH₂)Cl]²⁺ cations in water and in methanol-, ethanol-, and acetonitrile-water solvent mixtures. In the case oftrans-[Rh(en)₂Cl₂]⁺, the dependence of rate constants on mercury(II) concentration indicates reaction through a binuclear (Rh-Cl-Hg bridged) intermediate. The dependence of the equilibrium constant for the formation of this intermediate and of its rate constant for dissociation (loss of HgCl⁺) on solvent composition have been established. With the aid of measured solubilities, published ancillary thermodynamic data, and suitable extrathermodynamic assumptions, the observed reactivity trends for these mercury(II)-catalysed aquations are dissected into initial state and transition state components. The reactivity patterns for these three complexes are compared with those for mercury(II)-catalysed aquation of other chloro-transition metal complexes, particularlycis-[Rh(en)₂Cl₂]⁺, [Co(NH₃)₅Cl]²⁺, and [ReCl₆]^2–.     

Determination of the kinetic parameters of thermal decomposition of [Co(NH3)6]2(C2O4)3· 4H2O by Kissinger's method

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.

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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.

     

Thermal decomposition of rhombohedral double carbonates of dolomite type

DTA and TG studies in air were carried out for hydrothermally prepared rhombohedral double carbonates of dolomite type, CaMg(CO₃)₂, CaMn(CO₃)₂, CdMg(CO₃)₂, CdMn(CO₃)₂ and CdZn(CO₃)₂. The solid decomposition products in air have been compared to those obtained under hydrothermal conditions with CO₂ pressure. The dolomite [CaMg(CO₃)₂] decomposes in two stages both in air as well as under high CO₂ pressure. The other carbonates studied, follow a single stage decomposition in air and a two stage decomposition under hydrothermal condition. In air, the manganese containing carbonates CaMn(CO₃)₂ and CdMn(CO₃)₂, decompose to form mixed oxides of CaMnO₃ and CdMnO₃ respectively, while CdMg(CO₃)₂ and CdZn(CO₃)₂ decompose to their respective two mono oxides.

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Zusammenfassung Mittels DTA und TG in Luft werden die hydrothermisch hergestellten rhomboedrischen Doppelkarbonate (Dolomittyp) CaMg(CO₃)₂, CaMn(CO₃)₂, CdMg(CO₃)₂, CdMn(CO₃)₂ und CdZn(CO₃)₂ untersucht. Die in Luft erhaltenen festen Zersetzungsprodukte wurden mit denen verglichen, die unter hydrothermischen Bedingungen mit CO₂-Druck entstehen. Dolomit zersetzt sich sowohl in Luft als auch unter hohem CO₂-Druck in zwei Schritten. Die übrigen untersuchten Karbonate zersetzen sich in Luft in einem, unter hydrothermischen Bedingungen in zwei Schritten. In Luft zersetzen sich die magnesiumhaltigen Karbonate CaMn(CO₃)₂ und CdMn(CO₃)₂ unter Bildung der Mischoxide CaMnO₃ und CdMnO₃, während aus CdMg(CO₃)₂ und CdZn(CO₃)₂ jeweils die entsprechenden beiden Monoxide entstehen.

     

Studies on the reactions of aluminium oxides and hydroxides

The hydrothermal and decomposition reactions of differently ground gibbsite and its reaction products were studied. The samples were treated isothermally under hydrothermal conditions or in air, and the products were characterized by thermogravimetry and IR spectroscopy. It was found that the method and duration of grinding and the particle size of the starting gibbsite influenced the reactivity of the gibbsite itself and that of the primary reaction products. In a later step of the reaction sequence (hydrothermal rehydration of-alumina), the effects of the differences in the properties of the starting gibbsites were insignificant.

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Zusammenfassung Es wurden die hydrothermischen und Zersetzungsreaktionen verschiedener Gibbsitproben und deren Reaktionsprodukten untersucht. Die Proben wurden unter hydrothermischen Bedingungen oder in Luft isothermisch behandelt, die Produkte mittels TG und IR beschrieben. Es wurde festgestellt, da\ Art und Weise der Zerkleinerung und Korngrö\e des Gibbsit-Ausgangsmateriales die ReaktivitÄt von Gibbsit selbst, aber auch die der primÄren Reaktionsprodukte beeinflu\t. In spÄteren Schritten des Reaktionsverlaufes (hydrothermische Rehydratation von-Aluminiumoxid) besitzen Unterschiede in den Eigenschaften des Gibbsit-Ausgangsmateriales keinen Einflu\.

     

Re-determination of the crystal structure and investigation of thermal decomposition of the Chugaev’s salt, [Pt(NH3)5Cl]Cl3·H2O

The crystal structure of the salt [Pt(NH₃)₅Cl]Cl₃·H₂O has been re-determined by single crystal X-ray diffraction and the salt has been studied by the thermal analysis. It is shown that one molecule of crystallization water enters into the salt composition. Intermediate products of thermal decomposition of the salt have been isolated and explored by IR spectroscopy and powder X-ray diffraction.     

Decomposition thermique du trichlorure de ruthenium hexammine

The thermal decomposition of [Ru(NH₃)₆]Cl₃ leads between 200 and 400° in inert gas to metallic ruthenium through the intermediates [Ru(NH₃)₅Cl]Cl₂, [Ru(NH₃)₄Cl₂]Cl and [Ru(NH₃)₃Cl₃]. In the total decomposition $$[Ru(NH_3 )_6 ]Cl_3 \to Ru + 1/2N_2 + 3NH_3 + HCl + 2NH_4 Cl$$ finely divided ruthenium is obtained above 240°. In oxygen the same intermediates are formed, the final product, however, being the metal and its dioxide.     

Simultaneous thermoanalytical investigations on the rapid decomposition of pentamminecobalt(III) complexes

The thermal decomposition of [Co(NH3)₅CO₃]NO₃, [Co(NH₃)₅NO₂](NO₃)₂ and [Co(NH₃)₅H₂O](NO₃)₃ complexes was studied by simultaneous TG, DTG, DTA (Derivatograph-C), termogastitrimetry, continuous selective water detection, TG-MS, and XRD methods.Due to the nearly explosive reaction of these complexes the samples were heated in a labyrinth-type crucible after a 10-fold dilution with alumina.Through the quantitative determination of NH₃ and H₂O it was possible to reveal the subtleness of decomposition of these complexes.Based on the qualitative and quantitative results obtained by the different thermoanalytical techniques used the equations of decomposition are given for both stages of the reactions.

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Zusammenfassung Mittels simultaner TG, DTG, DTA (Derivatograph-C), weiterhin mittels Thermogastitrimetrie, kontinuierlicher selektiver Wasserdetektierung, TG-MS und XRD-Verfahren wurde die thermische Zersetzung der Komplexe [Co(NH₃)₅CO₃]NO₃, [Co(NH₃)₅NO₃](NO₃)₂ und [Co(NH₃)_sH₂O](NO₃)₃ untersucht.Wegen dem beinahe explosiven Verlaufes der Reaktion dieser Komplexe wurden die Proben in einem Labyrinth-Tiegel in zehnfacher Verdünnung mit Aluminiumoxid erhitzt.Mittels der quantitativen Bestimmung von NH₃ und H₂O war es möglich, die komplizierte Zersetzungsreaktion dieser Komplexe aufzuklären.Ausgehend von den mit Hilfe der verschiedenen thermoanalytischen Verfahren erhaltenen qualitativen und quantitativen Ergebnissen wurden die Zersetzungsgleichungen für beide Reaktionsschritte gegeben.

     

Etude par microcalorimetrie de la reactivite de deux ammoniacates de chlorure de manganese

The reaction [Mn(NH₃)₂]Cl₂+ 4NH₃ [Mn(NH₃)₆]Cl₂, which is of potential use in chemical heat pumps, was studied by means of differential scanning calorimetry. The thermodynamic conditions, the enthalpy of the reaction, and the heat capacity values for MnCl₂, [Mn(NH₃)₂Ch and [Mn(NH₃)₆Cl₂ were measured. The influence of the reaction kinetics of the experimental procedure and some parameters such as sample temperature, ammonia pressure and scanning rate was examined.

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Zusammenfassung Mittels DSC wurde die Reaktion [Mn(NH₃)₂]Cl₂+4 NH₃ [Mn(NH3_{) 6}]Cl₂ untersucht, die von potentieller Verwendung für chemische WÄrmepumpen ist. Thermodynamische Bedingungen, die Reaktionsenthalpie und WÄrmekapazitÄtswerte für MnCl₂, [Mn(NH₃)₂]Cl₂ und [Mn(NH₃)₆]Cl₂ wurden gemessen. Weiterhin wurde der Einflu\ des Versuchsablaufes und einiger Parameter, wie Probentemperatur, Ammoniakdruck und Scanning-Geschwindigkeit auf die Reaktionskinetik untersucht.

     

Synthese und Struktur von Ammin- und Amidokomplexen des Iridiums

Synthesis and Structure of Ammine and Amido Complexes of Iridium The reaction of (NH₄)₂[IrCl₆] with NH₄Cl at 300 °C in a sealed glass ampoule yields the iridium(III) ammine complex (NH₄)₂[Ir(NH₃)Cl₅], which crystallizes isotypically with K₂[Ir(NH₃)Cl₅] in the orthorhombic space group Pnma with Z = 4, and a = 1350.0(2); b = 1028.5(3); c = 689.6(2) pm. The reaction of (NH₄)₂[IrCl₆] with NH₃ at 300 °C, however, gives the already known [Ir(NH₃)₅Cl]Cl₂ beside a small amount of [Ir(NH₃)₄Cl₂]Cl₂. In pure form [Ir(NH₃)₅Cl]Cl₂ is obtained by ammonolysis of (NH₄)₂[Ir(NH₃)Cl₅] at 300 °C with NH₃. [Ir(NH₃)₄Cl₂]Cl₂ crystallizes triclinic (P1, Z = 1, a = 660,2(3); b = 680,4(3); c = 711,1(2) pm; α = 103,85(2)°, β = 114,54(3)°, γ = 112,75(2)°). The structure contains Cl^– anions and [Ir(NH₃)₄Cl₂]²⁺ cations with a trans position of the Cl atoms. Upon reaction of [Ir(NH₃)₅Cl]Cl₂ with Cl₂ one ammine ligand is eliminated yielding [Ir(NH₃)₄Cl₂]Cl, which is transformed to orthorhombic [Ir(NH₃)₄(OH₂)Cl]Cl₂ (Pnma, Z = 4, a = 1335,1(3); b = 1047,9(2); c = 673,4(2) pm) by crystallization from water. In the octahedral complex [Ir(NH₃)₄(OH₂)Cl]²⁺ the four ammine ligands have an equatorial position, whereas the Cl atom and the aqua ligand are arranged axial. Oxidation of (NH₄)₂[Ir(NH₃)Cl₅] with Cl₂ at 330 °C affords the tetragonal Ir^IV complex (NH₄)[Ir(NH₃)Cl₅] (P4nc, Z = 2, a = 702.68(5); c = 912.89(9) pm). Its structure was determined using the powder diagram. Oxidation of (NH₄)₂[Ir(NH₃)Cl₅] with Br₂ in water, on the other hand, gives (NH₄)₂[IrBr₆] crystallizing in the K₂[PtCl₆] type. Oxidation of (PPh₄)₂[Ir(NH₃)Cl₅] with PhI(OAc)₂ in CH₂Cl₂ affords the Ir^V amido complex (PPh₄)[Ir(NH₂)Cl₅].     

Thermal decompostion studies on nickel(II) bis(oxalato)nickelate(II) pentahydrate

The paper describes the synthesis and thermal decomposition of nickel(II)bis(oxalato)nickelate(II)pentahydrate, Ni[Ni(C₂O₄)2].5H₂O. The complex was characterized by elemental analysis, infrared, electronic, e.s.r., magnetic moment measurement and X-ray powder diffraction studies. The thermal decompostion of the complex led to NiO in air at about 338° and in nitrogen at about 720°. The activation energies (E ^*) for the dehydration and decompostion reactions in air and nitrogen were evaluated. Tentative reaction mechanisms have been suggested for the termal decompostion of the complex in air and nitrogen.

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Zusammenfassung Es wird die Synthese und thermische Zersetzung von Nickel(II) -bis(oxalato)- nickelat(II) - pentahydrat beschrieben: Ni[Ni(C₂O₄)2].5H₂O. Dieser Komplex wurde mittels Elementaranalyse, IR-Spektroskopie, ESR-Spektroskopie, der Messung des magnetischen Momentes sowie mittels Pulverdiffraktionsuntersuchungen charakterisiert. Im Ergebnis der thermischen Zersetzung entsteht NiO, in Luft bei etwa 338°, in Stickstoffatmosphäre bei ca. 720°. Die Aktivierungsenergien (E^*) der Dehydratations- und Zersetzungsreaktionen in Luft und in Stickstoff wurden ermittelt. Für die thermische Zersetzung des Komplexes in Luft bzw. in Stickstoff wurde ein Reaktionsmechanismus entwickelt.

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The authors thank the RSIC, CDRI, Lucknow for microanalysis, RSIC, NEHU, Shillong for i.r. spectra, RSIC, IIT, Madras for far i.r. spectra, RSIC, Nagpur University for thermal analysis, Dr. S. K. Datta for Forensic Science Laboratory, Guwahati, Assam for DSC and Dr. K. L. Deori of Dibrugarh University for X-ray powder diffraction photographs.     

Structural Characterization of trans-[Cr(NH3)4(H2O)Cl]Cl2 and trans-[Cr(NH3)4Cl2]l

Trans-[Cr(NH₃)₄(H₂O)Cl]Cl₂ (A) crystallizes in the monoclinic space group P2₁/m (No. 11) with a = 6.556(1), b = 10.630(5), c = 6.729(2) Å and β = 96.15(3)°. Trans-[Cr(NH₃)₄Cl₂]I (B) has monoclinic C2/m (No. 12) space group and a = 9.877(2), b = 8.497(2), c = 6.047(2) Å and β = 108.98(2)°. Both unit cells contain two formula units. Cr? Cl, Cr? O(H₂O) and three independent Cr? N(NH₃) distances for A are 2.98(1), 2.023(2), 2.067(2), 2.086(3) and 2.064(3) °. Cr? Cl and Cr? N(NH₃) bonds in B are 2.325(1) and 2.071(2) °. All octahedral angles are close to 90 and 180°. Both structures were refined to very low R values. Water molecule from trans-[Cr(NH₃)₄(H₂O)Cl]²⁺ is hydrogen bonded to both ionic chlorides. Cation and two anions form the motive which repeats itself in the crystal. Cations and anions of the second structure are distributed in layers. Each cation and anion have coordination number eight.     

Thermal decomposition of Co(II), Ni(II), Cu(II) and Zn(II) hippurates

The hippurates of Co(II), Ni(II), Cu(II) and Zn(II) were isolated from the solution, their quantitative composition and the way of coordination of metal — ligand were determined and the conditions and products of thermal decomposition during heating in air atmosphere up to 1273 K were studied. The complexes of Ni(II), Cu(II) and Zn(II) heated lose some water molecules and then decompose to MO. The hippurate of Co(II) heated loses some water molecules and then decomposes to CoO with intermediate formation Co₃O₄.

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Zusammenfassung Aus Lösung wurden die Co(II)-, Ni(II)-, Cu(II)- und Zn(II)-Salze der Hippursäure gewonnen, ihre quantitative Zusammensetzung sowie die Art der Koordination der Metall-Ligandenbindung bestimmt. Weiterhin wurden die Bedingungen und Produkte der thermischen Zersetzung beim Erhitzen in einer Luftatmosphäre bis 1273 K untersucht. Die Komplexe von Ni(II), Cu(II) und Zn(II) verlieren beim Erhitzen ein paar Moleküle Wasser und zersetzen sich anschlieend zu MO. Co(II)-hippurat gibt beim Erhitzen einige Moleküle Wasser ab und zersetzt sich dann über die Zwischenstufe Co₃O₄ zu CoO.