Thermal analysis, phase transitions and molecular reorientations in [Sr(OS(CH3)2)6](ClO4)2

Thermal analysis (TG/DTG/QMS), performed for [Sr(OS(CH₃)₂)₆](ClO₄)₂ in a flow of argon and in temperature range of 295–585 K, indicated that the compound is completely stable up to ca. 363 K, and next starts to decompose slowly, and in the temperature at ca. 492 K looses four (CH₃)₂SO molecules per one formula unit. During further heating [Sr(DMSO)₂](ClO₄)₂ melts and simultaneously decomposes with explosion. Differential scanning calorimetry (DSC) measurements performed in the temperature range of 93–370 K for [Sr(DMSO)₆](ClO₄)₂ revealed existence of the following phase transitions: glass ? crystal phase Cr5 at T _g  ≈ 164 K (235 K), phase Cr5 → phase Cr4 at $ T_{\text{c6}}^{\text{h}} $  ≈ 241 K, phase Cr4 → phase Cr3 at $ T_{\text{c5}}^{\text{h}} $  ≈ 255 K, phase Cr3 → phase Cr2 at $ T_{\text{c4}}^{\text{h}} $  ≈ 277 K, phase Cr2 ? phase Cr1 at $ T_{\text{c3}}^{\text{h}} $  ≈ 322 K and $ T_{\text{c3}}^{\text{c}} $  ≈ 314 K, phase Cr1 ? phase Rot2 at $ T_{\text{c2}}^{\text{h}} $  ≈ 327 K and $ T_{\text{c2}}^{\text{c}} $  ≈ 321 K and phase Rot2 ? phase Rot1 at $ T_{\text{c1}}^{\text{h}} $  ≈ 358 K and $ T_{\text{c1}}^{\text{c}} $  ≈ 347 K. Entropy changes values of the phase transitions at $ T_{\text{c1}}^{\text{h}} $ and $ T_{\text{c2}}^{\text{h}} $ (?S ≈ 79 and 24 J mol^?1 K^?1, respectively) indicated that phases Rot1 and Rot2 are substantially orientationally disordered. The solid phases (Cr1–Cr5) are more or less ordered phases (?S ≈ 7, 10, 4 and 3 J mol^?1 K^?1, respectively). Phase transitions in [Sr(DMSO)₆](ClO₄)₂ were also examined by Fourier transform middle infrared spectroscopy (FT-MIR). The characteristic changes in the FT-MIR absorption spectra of the low- and high-temperature phases observed at the phase transition temperatures discovered by DSC allowed us to relate these phase transitions to the changes of the reorientational motions of DMSO ligands and/or to the crystal structure changes.     

Ordering of Cu(II) ions in supported copper-titanium oxide catalysts

Two types of ESR spectrum (A and B) of exchange-coupled Cu²⁺ ions have been found for Cu-Ti-O catalysts at 77 K and 300 K. In associates A and B, the Cu²⁺ ions form a system with orbital ordering. The difference between the spectra is due to the difference between the ground states of adjacent Cu²⁺ ions in the associates: the ground states are $d_{x^2 } $ and $d_{y^2 } $ for A type associates and $d_{x^2 - y^2 } $ and $d_{z^2 - x^2 } $ for B type associates. The copper associates lie on the surface of the TiO₂ (anatase) support microparticles.     

The state of Cu2+ ions in concentrated aqueous ammonia solutions of copper nitrate

Stabilization of Cu²⁺ ions in concentrated aqueous ammonia solutions of copper nitrate in a wide range of ammonium ion concentrations has been studied by EPR and electronic absorption spectroscopy. Three types of Cu²⁺ associates with different types of orbital ordering have been identified. The ammonium ion concentration in a solution has a decisive effect on the type of orbital ordering of Cu²⁺ ions in associates. In all cases, Cu²⁺ ordering in associates is caused by the existence of bridging OH groups in the axial and equatorial positions of [Cu(NH₃) _n (H₂O)_{6 ? n} ]²⁺ complexes (n < 6). At a high concentration of ammonium ions, weakly bound associates of tetramminecopper with the $d_{x^2 - y^2 }$ ground state are formed. In solutions with low ammonium concentrations, bulky associates with the $d_{y^2 }$ and $d_{x^2 - z^2 }$ ground states and associates of Cu²⁺ ions with the $d_{x^2 - y^2 }$ ground state with hydroxyl groups in the equatorial plane and axial water molecules are formed.     

The volume and compressibility change for the formation of the LaSO 4 + ion pair at 25°C

The apparent molal volumes (φ_v) and adiabatic compressibilities [φ_K(S)] of La₂(SO₄)₃ solutions have been determined from density and sound speed data at 25°C. The large positive deviations of φ_v and φ_K(S) of La₂(SO₄)₃ from the limiting law have been attributed to the formation of the ion pair LaSO ₄ ⁺ . The observed values of φ_v and φ_K(S) have been used to estimate the change in the apparent molal volume and adiabatic compressibility for the formation of LaSO ₄ ⁺ from $$\Delta \phi (LaSO_4^ + ) = [\phi (obs.) - \phi (2La^{3 + } ,3SO_4^{2 - } )]/\alpha$$ where ?(2La³⁺, 3SO ₄ ^2? ) is the apparent molal volume or adiabatic compressibility of the free ions, and α is the degree of association. The value of \(\Delta \phi _v^o (LaSO_4^ + ) = \Delta \bar V^o (LaSO_4^ + ) = 22.8 \pm 1cm^3 - mole^{ - 1}\) and \(\Delta \phi _{K(S)}^o (LaSO_4^ + ) = \Delta \bar K_S^o (LaSO_4^ + ) = 85 \pm 20 \times 10^{ - 4} cm^3 - mole^{ - 1} - bar^{ - 1}\) at infinite dilution are in reasonable agreement with the values determined from the high-pressure conductance data of Fisher and Davis. The number of hydrated water molecules (ca. 11) associated with the formation of LaSO ₄ ⁺ determined from the volume and compressibility data are in good agreement.     

New garnet compounds A 3 2+ B 2 2+ C4+V 2 5+ O12(A = Ca,Cd; B = Mg,Zn, Co,Ni, Cu,Mn, Cd; C = Ge,Si)

Garnet compounds A ₃ ²⁺ B ₂ ²⁺ C⁴⁺V ₂ ⁵⁺ O₁₂ (A = Ca, Cd; B = Mg, Zn, Co, Ni, Cu, Mn, Cd; C = Ge, Si) (space group \(Ia\bar 3d\) , Z = 8) have been prepared by solid-phase synthesis in air at 900–1250°C. Most of these compounds melt incongruently or decompose in the solid phase. The isomorphic capacity of garnets and their homogeneity fields are discussed. The structures of Ca₃Zn₂GeV₂O₁₂ and Ca₃Cu₂GeV₂O₁₂ have been refined by the Rietveld method.     

Gas-phase reactions of CF2 with O(3P) to produce COF: Their significance in plasma processing

Reactions between CF₂ and O(³P) have been studied at 295 K in a gas flow reactor sampled by a mass spectrometer. The major reaction for CF₂ has been found to be $$CF_2 + O \to COF + F$$ with $$CF_2 + O \to CO + 2F(F_2 )$$ more than a factor of three slower. The rate coefficient for all loss processes for CF₂ on reaction with O is (1.8±0.4)×10^?11 cm³ s^?1. The COF produced in (18) undergoes a fast reaction with O to produce predominantly CO₂. $$COF + O \to CO_2 + F$$ It is uncertain from the results whether or not $$COF + O \to CO + FO$$ occurs, but in any event (19) is the major route. The rate coefficient for the loss of COF in this system [i.e., the combined rate coefficients for (19) and (20)] is (9.3±2.1)×10^?11 cm³ s^?1. Stable product analysis reveals that for each CF₂ radical consumed, the following distribution of stable products is obtained: COF₂ (0.04±0.02), CO (0.21±0.04), and CO₂ (0.75±0.05). Thus COF₂, which we assume is produced via $$CF_2 + O \xrightarrow{M} COF_2$$ is a very minor product in this reaction sequence. The measured rate coefficients demonstrate that reactions (18) and (19) are important sources of F atoms in CF₄/O₂ plasmas.     

Molecular magnets based on chain polymer complexes of copper(II) bis(hexafluoroacetylacetonate) with isoxazolyl-substituted nitronyl nitroxides

First isoxazolyl-substituted nitronyl nitroxides (L and $L^{Me_2 }$ ) were synthesized and characterized. Their reactions with Cu(hfac)₂ and Mn(hfac)₂ (hfac is hexafluoroacetylacetonate) afford the heterospin complexes [Cu(hfac)₂L] _n , [Cu₂(hfac)₄L] _n , $\left[ {Cu_2 (hfac)_4 L^{Me_2 } } \right]_n$ , $\left[ {Cu(hfac)_2 L^{Me_2 } } \right]_n$ , $\left[ {Cu(hfac)_2 L^{Me_2 } _2 } \right]$ , $\left[ {Cu(hfac)_2 L^{Me_2 } (MeCN)} \right]$ , [Mn(hfac)₂]₃L₄, and $\left[ {Me(hfac)_2 L^{Me_2 } } \right]_2$ . In the ligand L, the N atom of the isoxazole ring (NIz) has weak electron-donating properties. For example, the paramagnetic ligand in the chain polymer complex [Cu(hfac)₂L] _n acts as a bidentate bridging ligand coordinated through both O atoms of the nitronyl nitroxide group (O_N-O); the N_Iz and O_Iz atoms are not involved in the coordination. The introduction of Me groups into the isoxazole substituent results in an increase in the electron density on the N_Iz atom and enables the synthesis of the chain polymer complex $\left[ {Cu(hfac)_2 L^{Me_2 } } \right]_n$ , in which the bidentate bridging ligand $L^{Me_2 }$ is coordinated through the O_N-O and N_Iz atoms. In the mononuclear complexes $\left[ {Cu(hfac)_2 L^{Me_2 } _2 } \right]$ and $\left[ {Cu(hfac)_2 L^{Me_2 } (MeCN)} \right]$ , the paramagnetic ligand is coordinated only through the N_Iz atom. The solid heterospin Mn complexes [Mn(hfac)₂]₃L₄ and $\left[ {Mn(hfac)_2 L^{Me_2 } } \right]_2$ have a molecular structure. In these complexes, strong antiferromagnetic intracluster exchange interactions arise. The residual magnetic moments of the exchange clusters in the complex [Mn(hfac)₂]₃L₄ are ferromagnetically coupled, resulting in the increase in the effective magnetic moment (??_eff) of the complex with decreasing temperature in the range of 300??30 K. The thermomagnetic study of the complexes [Cu(hfac)₂L] _n , [Cu₂(hfac)₄L] _n , and $\left[ {Cu_2 (hfac)_4 L^{Me_2 } } \right]_n$ in the range of 2?C300 K revealed the ferromagnetic ordering at temperatures below 5 K. The ESR study of the solid complex $\left[ {Cu(hfac)_2 L^{Me_2 } } \right]_n$ showed that the decrease in its ??_eff in the temperature range of 30?C300 K is associated with the direct exchange interaction between the unpaired electrons of the nitronyl nitroxides of adjacent chains, whereas at temperatures below 30 K, only Cu²⁺ ions contribute to the magnetic susceptibility of the complex.     

Synthesis and magnetic properties of Cu0.5Fe0.5 ? x In x Cr2S4 (x = 0?0.4) solid solutions

Multistep synthesis with X-ray diffraction monitoring of the phase composition has been carried out, optimal synthesis parameters have been determined, and the magnetic properties of solid solutions between thiospinels with ordered tetrahedral A lattices (ferrimagnet Cu_0.5Fe_0.5Cr₂S₄ (T _C = 347 K) and anti-ferromagnet Cu_0.5In_0.5Cr₂S₄ (T _N = 35 K) have been studied. Both compounds crystallize in F $\bar 4$ 3m (T _d ² ) structure. Measurements over wide ranges of fields (0.05?C40 kOe) and temperatures (5?C300 K) highlighted the nature of magnetism in the samples; new magnetic species have been discovered.     

Nanosized sulfated zirconia as solid acid catalyst for the synthesis of 2-substituted benzimidazoles

The condensation reaction of o-phenylenediamine and arylaldehydes was investigated in the presence of nanosized sulfated zirconia (SO ₄ ^2? -ZrO₂) as the solid acid catalyst. Nanosized SO ₄ ^2? -ZrO₂ was prepared and characterized by the XRD, FT-IR, and SEM techniques. The results confirm good stabilization of the tetragonal phase of zirconia in the presence of sulfate. Reusability experiments showed partial deactivation of the catalyst after each run; good reusability can be achieved after calcinations of the recovered catalyst before its reuse.     

Diffusion and Ion Association in Concentrated Solutions of Aqueous Lithium, Sodium, and Potassium Sulfates

Taylor dispersion is used to measure mutual diffusion coefficients for aqueous Li₂SO₄ solutions at concentrations from 0.09 to 2.62 mol-dm^-3 at 25°C. The Li₂SO₄ results and previously reported diffusion coefficients for aqueous Na₂SO₄ and K₂SO₄ are compared with predictions made by treating the limiting electrolyte diffusion coefficients as reference values and applying corrections for nonideal solution behavior, ionic hydration, and viscosity changes as the concentration is raised. Good agreement is obtained if the M⁺ + SO ₄ ^2- ? MSO ₄ ^- (M = Li, Na, K) association equilibria are included in the analysis. Extents of formation of the MSO ₄ ^- ion pairs are evaluated by fitting Pitzer's mixed electrolyte equations for aqueous M⁺–MSO ₄ ^- –SO ₄ ^2- ions to osmotic coefficient data. Diffusion coefficients for hypothetical solutions of the completely dissociated M₂SO₄ electrolytes are calculated to illustrate the effects of ion association on diffusion. Association of the M⁺ and SO ₄ ^2- ions increases the overall mobility and thermodynamic driving forces for their diffusion.     

The Formation and Stability of the [FePy3Cl3]· Py Clathrate in the Pyridine–Iron(III) Chloride System: Phase Diagram and Solid–Gas Equilibria Study

The phase diagram of the pyridine–iron(III) chloride system has been studied for the 223–423 K temperature and 0–56 mass-% concentration ranges using differential thermal analysis (DTA) and solubility techniques. A solid with the highest pyridine content formed in the system was found to be an already known clathrate compound, [FePy₃Cl₃]·Py. The clathrate melts incongruently at 346.9 ± 0.3 K with the destruction of the host complex: [FePy₃Cl₃]·Py_(solid)=[FePy₂Cl₃]_(solid) + liquor. The thermal dissociation of the clathrate with the release of pyridine into the gaseous phase (TGA) occurs in a similar way: [FePy₃Cl₃]·Py_(solid)=[FePy2Cl₃]_(solid) + 2 Py_(gas). Thermodynamic parameters of the clathrate dissociation have been determined from the dependence of the pyridine vapour pressure over the clathrate samples versus temperature (tensimetric method). The dependence experiences a change at 327 K indicating a polymorphous transformation occurring at this temperature. For the process ${1 \over 2}[\hbox{FePy}_{3}\hbox{Cl}_{3}]\cdot \hbox{Py}_{\rm (solid)} = {1 \over 2}[\hbox{FePy}_{2}\hbox{Cl}_{3}]_{\rm (solid)} + \hbox{Py}_{\rm (gas)}$ in the range 292–327 K, ΔH $^{0}_{298}$ =70.8 ± 0.8 kJ/mol, ΔS $^{0}_{298}$ =197 ± 3 J/(mol K), ΔG $^{0}_{298}$ =12.2 ± 0.1 kJ/mol; in the range 327–368 K, ΔH $^{0}_{298}$ =44.4 ± 1.3 kJ/mol, ΔS $^{0}_{298}$ =116 ± 4 J/(mol K), ΔG $^{0}_{298}$ =9.9 ± 0.3 kJ/mol.     

The phase diagrams of the systems MgCl2 + MgB6O10 + H2O and MgSO4 + MgB6O10 + H2O at 323.15 K and Pitzer model

The solubilities and the relevant physicochemical properties of the systems MgCl₂ + MgB₆O₁₀ + H₂O and MgSO₄ + MgB₆O₁₀ + H₂O at 323.15 K were determined by the method of isothermal dissolution, and the phase diagrams and the diagrams of physicochemical properties versus composition were plotted. Both of the systems belong to a simple eutectic type, and neither double salts nor solid solution were found. Based on the extended Harvie-Weare (HW) model and its temperature-dependent equations, the value of the singlesalt Pitzer parameters ??⁽⁰⁾, ??⁽¹⁾, ??⁽²⁾, and C ^? for MgCl₂, MgSO₄, and Mg(B₆O₇)(OH)₆, the mixed ion-interaction parameters $\theta _{Cl, B_6 O_{10} }$ , $\theta _{SO_4 , B_6 O_{10} }$ , $\Psi _{Mg, Cl, B_6 O_{10} }$ , $\Psi _{Mg, SO_4 , B_6 O_{10} }$ , the average equilibrium constants (lnK _aver) of solids in the systems and the Debye-Hückel parameter A ^? were fitted. Using the Pitzer parameters and the average equilibrium constants of solids at equilibrium, the solubilities of the two systems at 323.15 K have been calculated. Comparisons between the calculated and experimental results show that the predicted solubilities agree well with experimental data.     

A theoretical and experimental investigation of the formation of S 2 - from CS2 by electron impact

Theoretical and experimental investigation of the formation of S ₂ ^- from CS₂ by electron impact has been carried out. Molecular orbital calculations show that some of the low lying states of CS ₂ ^- have lower potential energy in the bent geometries suggesting a transformation in the geometric structure of the precursor molecular ion, leading to the formation of S ₂ ^- . In contrast to the formation of S ₂ ^- and S ₂ ^- , the kinetic energy associated with S ₂ ^- is small and disproportionate to the increase in electron energy, indicating the formation of S ₂ ^- in vibrationally excited states due to the mechanism of its formation.     

Thermochemical investigation of natural antlerite

Thermal and thermochemical investigations of natural hydroxyl-bearing copper sulfate Cu₃SO₄(OH)₄??antlerite have been carried out. The stages of its thermal decomposition have been studied employing the Fourier-transform IR spectroscopy. The enthalpy of formation of antlerite from the elements ??_f H _m ^o (298.15?K)?=?(?1750?±?10)?kJ?mol^?1 has been determined by the method of oxide melt solution calorimetry. Using value of S _m ^o (298.15?K), equal to (263.46?±?0.47)?J?K^?1?mol^?1, obtained earlier by the method of adiabatic calorimetry, the Gibbs energy value of ??_f G _m ^o (298.15?K)?=?(?1467?±?10)?kJ?mol^?1 has been calculated.     

Adsorption affinity of anions on metal oxyhydroxides

The dependences of anion (phosphate, carbonate, sulfate, chromate, oxalate, tartrate, and citrate) adsorption affinity anions from geometric characteristics, acid-base properties, and complex forming ability are generalized. It is shown that adsorption depends on the nature of both the anions and the ionic medium and adsorbent. It is established that anions are generally grouped into the following series of adsorption affinity reduction: PO ₄ ^3? , CO ₃ ^2? > C₂O ₄ ^2? , C(OH)(CH₂)₂(COO) ₃ ^3? , (CHOH)₂(COO) ₂ ^2? > CrO ₄ ^2? ? SO ₄ ^2? .     

Thermodynamic study of metal corrosion and inhibitor adsorption processes in copper/N-1-naphthylethylenediamine dihydrochloride monomethanolate/nitric acid system: part 2

N-1-Naphthylethylenediamine dihydrochloride monomethanolate (N-NEDHME) was tested as a corrosion inhibitor for copper in 2 M HNO₃ solution using the standard gravimetric technique at 303–343 K. N-NEDHME acts as an inhibitor for copper in an acidic medium. Inhibition efficiency increases with increase in concentration of N-NEDHME but decreases with a rise in temperature. Thermodynamic parameters such as adsorption heat ( $ \Updelta H_{\text{ads}}^\circ $ ), adsorption entropy ( $ \Updelta S_{\text{ads}}^\circ $ ) and adsorption free energy ( $ \Updelta G_{\text{ads}}^\circ $ ) were obtained from experimental data of the temperature studies of the inhibition process at five temperatures ranging from 303 to 343 K. Kinetic parameters activation such as $ E_{a} $ , $ \Updelta H_{\text{a}}^\circ $ , $ \Updelta S_{\text{a}}^\circ $ and pre-exponential factors have been calculated and are discussed. Adsorption of N-NEDHME on the copper surface in 2 M HNO₃ follows the Langmuir isotherm model.     

Guest-host copper(I, II) complex Rb11[Cul(H2O)2][Cul 15 1 Cl24(CuIICl6)]. effect of the nature of the [Cu 2 1 (H2O)2]2+ guest on crystal structure formation

The crystals of {Rb₁₁[Cu ₂ ¹ ( H₂O)₂]}[Cu ₁₅ ¹ Cl₂₄(Cu^IICl₆)] (I) formed in the RbCl-CuCl-H₂O -( O₂, C₂H₂ ) system were studied by X-ray diffraction analysis and ESR spectroscopy. The cell is monoclinic, space group B2/m, Z = 2, a = 24.787(3), b = 13.126(2), c = 11.318(5) Å, γ = 122.36(1)? (DARCH automatic diffractometer, γ(MoKgα). The crystal structure of compound I is a guest-host type structure consisting of the {[Cu ₁₅ ¹ Cl₂₄Cu₁₁Cl₆]^13?}n anion layers oriented perpendicularly to the [010] direction and containing large octahedral cavities (edge length =12 Å) with a discrete [ Cu^IICl₆ ] octahedron lying inside the cavity. The Rb⁺ cations and the charged [Cu ₂ ¹ ( H₂O)₂]²⁺ guest species lie between the anion layers. The effect of the nature of the guest on host structure formation is considered using compounds I and Rb₁₁[Cu ₁₅ ¹ Cl₁₆Brd₆Cu^IICl₆ ) Cu-C=CH] as examples.     

Photoelectrochemistry of silicon in HF solution

Photoelectrochemical, photoelectrocatalytic, and electrochemical processes of silicon anodic oxidation and hydrogen evolution in aqueous HF solution are discussed in terms of thermodynamic stability of Si, oxides SiO, SiO₂, and Si surface hydrides. It is shown that photoelectrochemical oxidation of n-type low-resistivity silicon to SiO₂ is catalyzed by Si $^{+}$ photo-hole formation, whereas in the case of p-type Si, the feasibility of this reaction is predetermined by p-type conductivity. It is suggested that anodic oxidation of Si goes through the stage of SiO oxide formation and its subsequent oxidation to SiO₂. Such mechanism accounts for chemical inertness of Si phase in HF solutions as well as for selective, anisotropic, and isotropic etching of Si within E ranges from $-0.5$ to 0.35 V, $0.35-0.8~V,$ and $E > 0.8$ V, respectively. Hydrogen evolution reaction on Si surface proceeds at very large overpotential ( $\geq 0.5$ V) through the stage of surface Si hydride formation: $\mathrm {Si + H_{2}O + e^{-} \rightarrow (SiH)_{surf} + OH^{-}}$ (the rate determining step) and $\mathrm {(SiH)_{surf} + H_{2}O + e^{-} \rightarrow Si + H_{2} + OH^{-}}$ . Illumination-related effects of surface reactions relevant to selective and anisotropic etching and nano/micro-structuring of Si surface are discussed.     

Electrical conductances of aqueous sodium trifluoromethanesulfonate from 0 to 450°C and pressures to 250 MPa

The electrical conductances of dilute (0.001 to 0.1 mol-kg^?1) aqueous sodium trifluoromethanesulfonate (NaCF₃SO₃) solutions have been measured from 0 to 450°C and pressures to 250 MPa. The limiting molar conductance $\Lambda _0 $ increases with increasing temperature from 0 to 300°C and decreasing density from 0.8 to 0.3 g-cm^?3. Above 300°C, $\Lambda _0 $ is nearly temperature independent, but increases linearly with decreasing density. The logarithm of the molal association constant of NaCF₃SO₃ calculated at temperatures from 372 to 450°C is represented as a function of temperature (Kelvin) and density of water (g-cm^?3) by $$\log K_m = 0.888 - 330.4/T - (12.83 - 5349/T)\log \rho _w $$ The relative strengths of NaCF₃SO₃ and NaCl are similar within the accuracy of the current measurements over the limited range of temperature and pressure that could be investigated here.     

The thermodynamic parameters of oxygen nonstoichiometry defects in lanthanum cobaltite doped with acceptor impurities (Sr and Ni)

The oxygen nonstoichiometry δ of lanthanum cobaltite doped with acceptor impurities (Sr and Ni), La_{1 ? x} Sr_xCo_0.9Ni_0.1O_{3 ? δ} (x = 0.1, 0.3), was studied by high-temperature thermogravimetry over the temperature and pressure ranges 723 K ≤ T ≤ 1373 K and 10^?3 atm ≤ $p_{O_2 } $ ≤ 1 atm. The partial replacement of cobalt with nickel and lanthanum with strontium increased the oxygen nonstoichiometry δ. The partial molar enthalpies $\Delta \bar H^\circ _O $ and entropies $\Delta \bar S^\circ _O $ of solution of oxygen in the solid phase were calculated. Models of point defect formation were suggested and analyzed. The equilibrium constants of formation and concentrations of predominant point defects, ionized oxygen vacancies V _o ^.. , holes Me _Co ^. (Co _Co ^. and Ni _Co ^. ), and electrons Me _Co ^′ (Co _Co ^′ and Ni _Co ^′ ) localized on 3d transition metals, were determined by nonlinear regression from the experimental and theoretical logp $p_{O_2 } $ ?δ dependences.