Gibbs Energy Of Formation Research Articles

On the Equilibrium Intermetallic Phase in Mg-Nd-Ag Alloys

The equilibrium intermetallic phase in Mg-Nd-Ag alloys has not been well understood. In this work, intermetallic particles in the solution-treated microstructure of commercial magnesium alloy QE22 (Mg-2.5Ag-2.0Nd-0.7Zr, wt pct) have been investigated using scanning electron microscopy, electron diffraction, atomic-resolution imaging and mapping techniques of scanning transmission electron microscopy (STEM) and thermodynamic modelling. The intermetallic particles are distributed in the inter-dendritic regions. They have coarse irregular shape and share the same crystal structure. The intermetallic phase (designated δ) is determined to have an orthorhombic structure (space group Cmcm, a = 1.02 nm, b = 1.18 nm, c = 1.00 nm) and a composition of NdAgMg11, which are different from those reported previously. An atomic model is proposed for the δ phase based on atomic-resolution STEM images and atomic-scale energy-dispersive X-ray spectroscopy maps. The δ lattice is structurally related to that of Mg12Nd phase in binary Mg-Nd alloys. The Gibbs energy of formation of NdAgMg11 is determined from the equilibrium study at 793 K (520 °C), including the entropy of formation using the present experimental phase analysis data obtained at lower temperature. Implications to the formation temperature range and thermal stability of this phase and alloy solidification are discussed based on the calculated Mg-Nd-Ag phase diagram and Scheil solidification paths of alloys.

Thermochemical Evaluation of Standard Electrode Potential and Gibbs Energy of Formation of PuCl3 in LiCl-KCl Eutectic Melt

This paper deals with the estimation of and of the Pu Pu redox couple in LiCl-KCl eutectic melt using statistical data fitting of experimental data. The value was also estimated in our laboratory at 723 and 773 K using logarithmic analysis of semi-integral voltammograms and chronopotentiograms. From semi-integral curves, was found to be −2.888 0.021 and −2.810 0.021 V at 723 and 773 K, respectively, whereas it was −2.851 0.020 V at 773 K from the analysis of chronopotentiograms. Based on subsequent statistical analysis, we recommend the following expressions for and applicable for the temperature range 673 to 823 K: and The value in LiCl-KCl eutectic melt was estimated from calculated for the reaction using FactSage package, and it was expressed as

Evaluation of reaction spontaneity for acidic and reductive dissolutions of corrosion metal oxides using HyBRID chemical decontamination

Complete sets of reaction mechanisms are proposed in the acidic and reductive dissolution of magnetite, nickel ferrite, and chromite using the HyBRID (Hydrazine Based Reductive metal Ion Decontamination) process for the decontamination of a primary coolant system of nuclear power plant. Hydrazine participated in the reaction pathway of reducing ferric ions to ferrous ions and simultaneously regenerating oxidized cupric ions into cuprous ions. The data of the heat capacity, the heat of formation, the entropy of formation, and the Gibbs energy of formation for all chemical species and ions were collected from the HSC Chemistry 9 database. The enthalpy, entropy, and Gibbs energy changes of reactions were calculated in the temperature range of 298.15–373.15 K for individual reactions. The degree of spontaneity decreased with the increase of the temperature. The reaction spontaneity was significantly enhanced by addition of hydrazine and slightly increased by further addition of copper sulfate.

Thermodynamic Properties of Montecellite

A thermochemical study of natural calcium and magnesium orthosilicate monticellite (Ca1.00Mg0.95$${\text{Fe}}_{{0.05}}^{{2 + }}$$)[SiO4] from the Khabarovsk Territory, Russia, was carried out on a Tian–Calvet microcalorimeter. The enthalpy of formation from elements Δf$$H_{{{\text{el}}}}^{^\circ }$$(298.15 K) = –2238.4 ± 4.5 kJ/mol was determined by high-temperature melt solution calorimetry. The enthalpy and Gibbs energy of formation of monticellite of theoretical composition of CaMg[SiO4] are calculated: Δf$$H_{{{\text{el}}}}^{^\circ }$$(298.15 K) = –2248.4 ± 4.5 kJ/mol and Δf$$G_{{{\text{el}}}}^{^\circ }$$(298.15 K) = –2130.5 ± 4.5 kJ/mol.

In‐situ microcalorimetry study on thermodynamic functions of Cu 2 O nanocubes

Four different sizes of cuprous oxides (Cu2 O) nanocubes in the range of 40–120 nm were synthesised by liquid phase reduction method. The morphology, size, and structure of synthesised Cu2 O nanocubes were characterised by scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. In-situ microcalorimetry was used to calculate the conventional and surface thermodynamic functions of Cu2 O nanocubes by combining thermodynamic principles and transition state theory. The effect of particle size on conventional thermodynamic functions and surface thermodynamic functions were investigated and analysed, whose results were supported by the established thermodynamic models. Results showed that both the standard molar enthalpy of formation and the standard molar entropy of formation were increased with decreasing particle size, while the standard molar Gibbs energy of formation decreased. Also, the molar surface Gibbs energy, molar surface enthalpy, and molar surface entropy grew with the reduction of particle size, which correlated well with the models. Such a property is of scientific significance for enriching and developing disciplines such as surface physics and surface thermodynamics.

Experimental and ab initio study of the Ag–Li system for energy storage and high-temperature solders

The standard enthalpies of formation of the Ag30Li70 and Ag20Li80 gamma phases (cubic, sg. I-43 m) were measured using the solution calorimetry method; the standard enthalpy of formation of the Ag10Li90 alloy, corresponding to a hypothetical γ phase, was determined using the same method. All the measured and literature values of the standard enthalpies of formation of the Ag–Li intermetallic phases were compared with the data calculated using ab initio for stable and unstable phases and Miedema’s model. The XRD pattern for a sample with Ag30Li70 was obtained and it was verified that it contained the γ phase, as expected. Moreover, the structure of the γ-phase for the Ag4Li9 disordered phase was minimized and the vibrational heat capacity at constant volume and the thermal coefficient of linear expansion were calculated using ab initio methods. The simulated XRD pattern of the latter phase was compared with the experimental pattern. It was determined that only one gamma phase, with a homogeneity range not wider than 0.69 ≤ x(Li) ≤ 0.73, is stable for T ≥ 298 K. Furthermore, besides AgLi-β with a homogeneity range of 0.50 ≤ x(Li) ≤ 0.60 at 298 K, a cubic Ag15Li49-β is stable for x(Li) = 0.77. The entropy term stabilizes the cubic structure of the AgLi-β which can be tetragonal at 298 K. The enthalpies and Gibbs energies of formation were calculated at 298, 320, 425, and 600 K. A new “map” of the phases in equilibrium at different temperatures is proposed.

Effects of oxygen partial pressure on the thermodynamics of CaO–SiO2–VOx system at 1873 K

AbstractIn this study, two aspects concerning with the thermodynamics of CaO–SiO2–VOx system were investigated. One aspect is about the effects of oxygen partial pressure on the phase relationships in CaO–SiO2–VOx system at 1873 K, and the other is the measurement of the standard Gibbs energy of formation of the vanadium compounds. In the first aspect, the phase relationships in CaO–SiO2–VOx system at 1873 K under oxygen partial pressure of 1.7 × 10−9 atm were determined, and the isothermal section diagram was constructed. Furthermore, by comparing this diagram with that under 6.9 × 10−11 atm, the effects caused by oxygen partial pressure on this system were elucidated. With the increase in oxygen partial pressure, the compound CaV2O4 that exists stably under 6.9 × 10−11 atm is oxidized to V2O3 and CaVO3. The solubility limit of V2O3 in liquid phase also increases remarkably, which results in the enlargement of the single liquid area. In the second aspect, the standard Gibbs energy of formation of CaV2O4, CaVO3, V2O3, and Ca2Si1−δVδO4 (0 < δ < 0.1) at 1873 K were measured. The determined values for CaV2O4 and CaVO3 are −1 259 468.9 ± 5090.5 J/mol and −963 479.8 ± 3298.6 J/mol, respectively. Then, the limit of oxygen partial pressure for CaV2O4 existing stably at 1873 K is determined to be 4.4 × 10−10 atm.

Study of thermodynamic properties of SrThF6(s) in SrF2-ThF4 system using solid state electrochemical cell method

The fission product strontium (Sr), after generation in the reactor due to fission of 233U, might exist as SrF2 in the molten fluoride medium of molten salt reactor (MSR) using fluoride carrier salts. The high temperature interactions between the strontium fluoride (SrF2) with the fertile fuel component and thorium fluoride (ThF4) leads to form single ternary compound SrThF6(s). The Gibbs energy of formation is the driving force for formation of any compound. In the present study, standard molar Gibbs energy of formation SrThF6(s) has been determined using an e.m.f. technique using CaF2(s) as solid electrolyte. Using the experimental thermodynamic data, to study the stability domain of SrThF6(s), the chemical potential diagram of Sr-Th-F-O system and ternary phase diagram of Sr-Th-F2 system have been calculated.

Determination of Gibbs energy of formation of LiThF5, LiTh2F9, and LiTh4F17 in Li-Th-F system by using solid electrolyte galvanic cell

The LiF-ThF4 system has been considered as reference fuel solvent for molten salt reactor. The high-temperature interaction of LiF-ThF4 leads to formation of a number of complex fluoride compounds. The study is focused on determination of experimental thermodynamic properties of the compounds in this system. The Gibbs energy of formation of LiThF5 (s), LiTh2F9 (s), and LiTh4F17 (s) has been measured by solid electrolyte galvanic cell method and the Gibbs energy of formation of these compounds as a function of temperature were expressed as $$ {\Delta}_{\mathrm{f}}G{}^{\circ}{}_{\mathrm{m}}\left({\mathrm{LiThF}}_5,\mathrm{s},T\right)\ \mathrm{kJ}\ {\mathrm{m}\mathrm{ol}}^{-1}=\left(-2738.7\pm 0.6\right)+\left(0.4050\kern0.5em \pm 0.0007\right)\cdotp \left(T/\mathrm{K}\right) $$ $$ {\Delta}_{\mathrm{f}}G{}^{\circ}{}_{\mathrm{m}}\left({\mathrm{LiTh}}_2{\mathrm{F}}_9,\mathrm{s},T\right)\ \mathrm{kJ}\ {\mathrm{m}\mathrm{ol}}^{-1}=\left(-4885.1\pm 0.8\right)+\left(0.7430\pm 0.0009\right)\cdotp \left(T/\mathrm{K}\right) $$ $$ {\Delta}_{\mathrm{f}}G{}^{\circ}{}_{\mathrm{m}}\left({\mathrm{LiTh}}_4{\mathrm{F}}_{17},\mathrm{s},T\right)\ \mathrm{kJ}\ {\mathrm{m}\mathrm{ol}}^{-1}=\left(-9126.5\pm 2.6\right)+\left(1.3801\pm 0.0034\right)\cdotp \left(T/\mathrm{K}\right) $$ The heat capacities of these compounds were also measured using differential scanning calorimeter. Using the experimental thermodynamic data, the thermodynamic tables of LiThF5 (s), LiTh2F9 (s), and LiTh4F17 (s) were constructed and the ternary phase diagram of Li-Th-F system was calculated to study the stability domain and coexisting phases of these compounds.

Wetting of liquid aluminum alloys on pure titanium at 873-973 K

The wetting behaviour of Al alloys (i.e., 6061 Al and 4043 Al alloys) on the surface of pure titanium was studied by sessile drop method at temperatures of 873–973K under high vacuum with ˜10−4 Pa. All wetting processes were divided into two stages: in the nonlinear stage, the formation of a compact intermetallic layer (Ti7Al5Si12) blocked the mass transfer at solid/liquid (S/L) interface and deteriorated wetting, while the formation of loose phase (Al3Ti) at triple line region can removed the oxide film and improved wettability. The wetting activation energy (56kJ/mol for a 6061Al/Ti system, and 71kJ/mol for a 4043Al/Ti system) corresponded to the sum of the difference in surface energy per molar area between α-Ti and TiO2 (27.2kJ/mol), and the Gibbs energy of formation for Al3Ti (30kJ/mol) or the decomposition energy for Ti7Al5Si12 (48kJ/mol). In the near-linear stage, the droplet spread on the surface of intermetallic compound (IMC). The spreading dynamics for 6061 alloy satisfied the Jiang’s empirical equation, and for 4043 alloy satisfied the viscous dissipation-limited model. The interfacial reaction had little effected on a droplet spreading, while the viscous friction drove the spread of 4043 alloy on precursor film in the near-linear stage.

Standard thermodynamic properties for the energy grade evaluation of fossil fuels and renewable fuels

Increasing development of future fuels, such as fossil fuels and renewable fuels, requires the evaluation method and data of fuels’ energy grade, which is derived from the enthalpy and exergy. However, few models can simultaneously and accurately predict the enthalpy and exergy. This work proposed prediction models to calculate the standard enthalpy and standard exergy of fuels. The models were established under the unified thermodynamic reference system, ensuring the thermodynamic consistency and the reliability of prediction result. The models need only value of the standard combustion heat and do not require composition of the fuel. The model functions are simple and easy for application. Model parameters were regressed based on the data of the standard enthalpy of formation and the standard Gibbs energy of formation of 194 typical fuel representatives. The high accuracy of new models was proved by comparison with 5 traditional models. Then, the new models were used to estimate the energy characteristics of 39 typical future fuels, including biodiesel, alcohol fuel, cellulosic fuel, marsh gas, and municipal refuse. Finally, the standard thermodynamic properties of these fuels were calculated, and some new opinions regarding the energy characteristics of future fuels were discussed.

Room Temperature Gibbs Energies of Hydrogen-Bonded Alcohol Dimethylselenide Complexes.

A number of hydrogen-bonded complexes, formed between an alcohol donor and dimethylselenide, have been detected experimentally, at room temperature in the gas phase using FTIR spectroscopy. The Gibbs energy of complex formation has been determined from the measured integrated absorbance of the hydrogen-bonded OH stretching band and the calculated oscillator strength of the associated transition. The OH stretching frequency and Gibbs energy of the selenium hydrogen-bonded complexes are compared to those found in complexes with the same donor molecule and either dimethylether (O) or dimethylsulfide (S) as the acceptor molecule. For a given donor, we found a similar OH stretching frequency in the complexes for each of the three acceptors O, S, and Se. However, the Gibbs energies were found to be less positive (i.e., stronger bound) for the dimethylether complexes (OH·O), as compared to the dimethylsulfide (OH·S) and dimethylselenide (OH·Se) complexes, with the latter two having comparable Gibbs energies.

Comparative analysis of experimental methods for determining thermodynamic parameters of formation of multi-component molecular crystals: Benefits and limitations

In this work, we have studied the processes of dissolution of 4-aminobenzoic acid (PABA) two-component crystals with 6-methyluracil (6-MeUr), pyrazinamide (PyrAm) and emoxypine (EMX) in the pH 7.4 phosphate buffer. The thermodynamic functions of cocrystal/salt formation have been estimated from the cocrystal/salt solubility and the corresponding solubility of the pure compounds at various temperatures. By analysing the investigated binary systems, we have compared the accuracy of different experimental methods in evaluating the thermodynamic stability of two PABA cocrystals and one salt: the method of phase solubility diagrams and the cocrystal solubility method. A qualitative evaluation of the comparative stability of the cocrystals and salt has been conducted by the competitive reactions method. The lowest value of the Gibbs energy of formation has been found in the PABA cocrystal with 6-MeUr. The fact that the PABA salt with EMX has the highest absolute value of the Gibbs energy of formation is associated with proton transfer.

Excess Gibbs energy of the binary mixed micelle formation between ionic and non-ionic surfactants in the set of: Sodium-cholate, sodium-deoxycholate, Brij S10 and Brij 58 at T = (283.15–323.15) K

Molar excess Gibbs energy of mixed micelle formation (ge) between ionic and non-ionic surfactants in the set of the following surfactants: sodium-cholate (SC), sodium-deoxycholate (SDC), Brij S10 (BS) and Brij 58 (B58) can be described by first order Margules function. The Regular Solution Theory (RST) hypothesis of zero excess entropy cannot be accepted with these systems of investigated surfactants. Molar excess entropy is probably the result of conformational entropy, while the configurational entropy is zero, and these two facts are the bases for the description of ge by first order Margules function. The interaction coefficient between the different building units of the investigated binary surfactant systems has greater value than 0, which means that there are antagonistic interactions between the surfactant molecules in the mixed micelles. According to the 1H-1H ROESY 2D spectra there are interactions between the hydrogens from the angular methyl groups of the SC (SDC) steroid skeleton and the hydrogen from the middle and terminal part of the B58 (BS10) hydrocarbon chain in the mixed micelles. The intensities of the cross-peaks and the interaction coefficients decrease with temperature, which suggests that with temperature increase the mixed micelle becomes more diffuse, i.e. less compact. There are cross-peaks in the ROESY 2D spectra between the building units of the mixed micelles, which mean that mixed micelles are formed, but the peaks don't give information about the synergistic or antagonistic effects between the surfactants.

Electrochemical behavior and extraction of zirconium on Sn-coated W electrode in LiCl-KCl melts

To recover metallic Zr from LiCl-KCl melts, the electroreduction of Zr(IV) ion was studied employing a variety of electrochemical methods on W and Sn-coated W electrodes. Zr(IV) ion was reduced to metallic Zr through two consecutive steps on W electrode: Zr(IV) + 2e− → Zr(II) and Zr(II) + 2e− → Zr, whereas one-step four-electron transfer on Sn-coated W electrode, i.e, xSn + 4e− + Zr(IV) = SnxZr. The formation of different Sn-Zr intermetallic compounds SnxZr resulted in three reduction peaks occurring at more positive potential than that of Zr(IV) on the W electrode, which was detected using cyclic voltammetry (CV) and square wave voltammetry (SWV). Meanwhile, the thermodynamic data, such as partial molar Gibbs energy and activity of Zr in Sn-Zr alloys and standard molar Gibbs energy of formation for Sn-Zr compound, were evaluated by open circuit chronopotentiometry (OCP). Furthermore, galvanostatic electrolysis (GE) at 0.1 A and potentiostatic electrolysis (PE) at −0.85 V were performed on liquid Sn electrode, and electrolytic products were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS). Experimental results indicated that metallic Zr was recovered and Sn2Zr was prepared on liquid Sn electrode in LiCl-KCl-K2ZrF6 melts.

Production of silumins using silicon production waste

The paper presents a review of existing methods to produce silumins. The possibility of obtaining foundry alloys using amorphous microsilica is shown. Different methods of adding SiO 2 particles into molten aluminum are studied: in the form of aluminum powder — SiO 2 master alloy tablets, particle mixing in the melt at the liquidus temperature and introducing SiO 2 together with a stream of argon. The paper provides calculations of Gibbs energy formation and change enthalpy for silicon reduction by aluminum from its oxide. Calculations demonstrated the thermodynamic possibility of silumin production using amorphous microsilica. The effect of alloying additives and impurities on the silicon reduction behavior is determined. It is found that magnesium can be used as a surface-active additive to remove oxygen from dispersed particle surfaces and reduce silicon from its oxide. It is determined that the method of aluminum-silicon alloy production by introducing amorphous microsilica preheated to 300 °С into the aluminum melt (t = = 900 °С) together with argon stream (with subsequent intensive mixing) features higher efficiency since it ensures producing aluminum-silicon alloys containing more than 6 wt.% of silicon and microstructure of pre-eutectic foundry silumins. Industrial application of the proposed method will improve the efficiency of the existing silumin production process due to savings on purchasing commercial crystalline silicon. Moreover, this technology will minimize the environmental impact by reducing the volume and subsequent eliminating sludge fields used as landfills for storing dust from silicon gas treatment systems containing up to 95 wt.% of amorphous microsilica.

Thermodynamic properties of cerium molybdate

AbstractCe2(MoO4)3is a harmful phase formed in waste glasses from nuclear fuel. To determine the third-law entropy of Ce2(MoO4)3, the isobaric heat capacities,$C_{p,m}^^\circ $, were measured with a relaxation-method instrument at 2–300 K. The standard entropy,$\Delta _0^TS_{\rm{m}}^^\circ $, at 298.15 K was determined with fitting functions including the Debye–Einstein formula including electronic and spin-wave terms. The Néel temperature,TN, was estimated by extrapolation from the magnetic term in this fitting function. The phase stability of Ce2(MoO4)3is discussed in terms of its standard Gibbs energy of formation,${\Delta _f}G_{\rm{m}}^^\circ $, which was derived by combining the values for$S_m^^\circ $determined in this study with reference data for the standard enthalpy of formation,${\Delta _f}H_{\rm{m}}^^\circ $.

Determination of thermodynamic properties of Bi2Mo3O12 (s), Bi2MoO6 (s) and Bi6Mo2O15 (s)

The standard molar Gibbs energy of formation of monoclinic phase of Bi2MoO6 (s) was determined by measuring the equilibrium oxygen partial pressures in the Bi (l) - MoO2 (s) -Bi2MoO6 (s) phase field using solid electrolyte based emf cells and it is given by the following expression: ΔfGm°<Bi2MoO6>±0.9/kJmol-1=-1382.3+0.5064(T/K)(T:773-1023K) The molar heat capacities of Bi2Mo3O12 (s), Bi6Mo2O15 (s) and Bi2MoO6 (s) were experimentally measured employing a differential scanning calorimeter. The heat capacities measured over a temperature range is given by: CP<Bi2Mo3O12>(JK-1mol-1)±16.4=416.7-7.1×10-3T-8.8×106T-2(T:328-818K)CP<Bi6Mo2O15>(JK-1mol-1)±23.4=529.8+67.9×10-3T-6.3×106T-2(T:318-808K)CP<Bi2MoO6>(JK-1mol-1)±8.8=221.4-1.5×10-3T-3.9×106T-2(T:318-818K)The internal consistency of the measured thermodynamic data of Bi2MoO6 (s) has been verified.

Recycling of ultrafine NdFeB waste by the selective precipitation of rare earth and the electrodeposition of iron in hydrofluoric acid

In this work, a simple and sustainable approach is proposed to recover rare earths and iron from an ultrafine NdFeB waste. Rare earths are directly recovered by one-step precipitation in hydrofluoric acid and the dissolved iron by electrodeposition. The rate constant and activation energy of the reaction of rare earth hydroxide with hydrofluoric acid are investigated to understand the kinetics of iron leaching and rare earth precipitation. The rare earth precipitation is much faster than the iron leaching, enabling the rare earths separation from iron after a complete iron dissolution. The cathodic deposits of iron were characterized by X-ray photoelectron spectrometer (XPS) and scanning electron microscope (SEM). The nano-scale FeF2(s) and Fe(s) were deposited on Pt electrode in hydrofluoric acid solution with pH 2.3 and pH 2.89, respectively. The reduction of Fe(III) to Fe(0) was investigated by cyclic voltammetry, chronopotentiometry and open circuit chronopotentiometry. This reduction was a quasi-reversible process which was controlled by diffusion. The temperature dependence of the diffusion coefficient was established as lnD = −9.84 − 1805.43/T and the activation energy value of the diffusion process was calculated to be −15.01 kJ mol−1. The relationship between the Gibbs energy of intermetallic Fe-Pt formation and the temperature was established to be ΔG = −487.53 + 0.936T. The hydrofluoric acid after the electrodeposition could be recycled for the leaching of the ultrafine NdFeB waste again.

An experimental calorimetric and a DFT + U study of the thermodynamic properties of [formula omitted] and [formula omitted

A calorimetric and thermodynamic investigation of two alkali-metal uranyl tungstates, Cs4UO24WO5W2O8O2(cr) and Cs4[UO27WO53O3](cr), was undertaken. Both phases were synthesized by solid-state sintering of a mixture of cesium nitrate, tungsten (VI) oxide and gamma-uranium (VI) oxide at high temperature. The synthetic products were characterized by X-ray powder diffraction and X-ray fluorescence methods. The enthalpies of formation of both phases were determined using HF-solution calorimetry giving ΔfHmoT=298.15K,Cs4UO24WO5W2O8O2,cr=-9239±17kJ·mol-1 andΔfHmoT=298.15K,Cs4UO27WO53O3,cr=-13008±23kJ·mol-1. The low-temperature heat capacity, Cp,mo, was measured using adiabatic calorimetry from T = 5 K to 324 K for Cs4UO24WO5W2O8O2cr and from T = 5 K to 325 K for Cs4UO27WO53O3cr. Using these Cp,moT data, the third law entropy at T = 298.15 K, Smo, is calculated as (931 ± 4) J∙K−1∙mol−1 for Cs4UO24WO5W2O8O2cr and (1262 ± 8) J∙K−1∙mol−1 for Cs4UO27WO53O3cr. These new experimental results, together with literature data, are used to calculate the Gibbs energy of formation, ΔfGmo, for both phases giving: ΔfGmoT=298.15K,Cs4UO24WO5W2O8O2,cr=-8623±18kJ·mol-1 and ΔfGmoT=298.15K,Cs4UO27WO53O3,cr=-12171±24kJ·mol-1. Smoothed Cp,moT values between 0 K and 320 K are presented, along with values for Smo and the functions HmoT-Hmo0 and GmoT-Hmo0, for both phases. Based on these data, the enthalpy of the intercalation reaction Cs4UO24WO5W2O8O2cr+3UO3cr,γ→Cs4UO27WO53O3cr at 298 K was determined as -98±29kJ·mol-1. A value of -90.3kJ·mol-1 at 0 K was obtained from DFT + U calculations. The results show the potential of using DFT + U simulations to understand solid-state reactions involving crystalline phases having 5d- and 5f-elements.