Standard enthalpy of formation of lithium diphosphate

Khaled, H. Gmati-Ben; Khattech, Ismail; Jemal, M.

doi:10.1016/j.jct.2013.03.009

Cited by 8 publications

(5 citation statements)

References 11 publications

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“…Considering this value with that obtained previously with Li and Na diphosphates [13,14], the drawing of the standard molar enthalpy of formation of the diphosphates as a function of that of the oxides (Fig. 4) shows a straight line with R 2 = 0.9739, suggesting a high correlation between these quantities and allowing to estimate the standard molar enthalpy of formation of potassium diphosphate as -3,187.8 kJ mol -1 .…”

Section: Discussionsupporting

confidence: 75%

“…This value needs to be checked by more recent experimental techniques. This work is the continuation of previous ones [13,14] and deals with a new determination of the standard molar enthalpy of formation of rubidium diphosphate through various processes of dissolution and mixing in aqueous phosphoric acid solutions [15] 'NH 4 H 2 PO 4 ' of a purity higher than 99 % (Fluka), were ground, in the appropriate proportion, in an agate mortar. The mixture was heated in a furnace using a platinum crucible.…”

Section: Introductionmentioning

confidence: 93%

“…Taking into account the enthalpies of formation of NaNO 3 (s), RbNO 3 (s), and Na 4 P 2 O 7 [14,20], we can derive that of rubidium diphosphate (Rb 4 P 2 O 7 ), at 298.15 K as being -3,183.7 kJ mol -1 . Because of the lack of errors on literature data, accuracy on this quantity cannot be evaluated.…”

Section: Mixing Processesmentioning

confidence: 99%

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Standard molar enthalpy of formation of rubidium diphosphate

Khaled

Khattech

Jemal

2014

J Therm Anal Calorim

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Rubidium carbonate (Rb 2 CO 3 ) and ammonium dihydrogen phosphate (NH 4 H 2 PO 4 ) were used for synthesizing rubidium diphosphate (Rb 4 P 2 O 7 ). The purity of the latter compound was checked up by X-ray diffraction. Rb 4 P 2 O 7 was involved in an hypothetical reaction and dissolved together with the other components in a 3.85 % (m/m) phosphoric acid solution, using a C-80 SETARAM calorimeter. Mixing processes were also realized in the calorimeter in order to get the standard molar enthalpy of formation of rubidium diphosphate (Rb 4 P 2 O 7 ). For that a thermochemical cycle was investigated and the obtained value for the standard molar enthalpy of formation of rubidium diphosphate is (-3,183.7) kJ mol -1 . The result is about 1.8 % lower than literature value.

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Section: Discussionsupporting

confidence: 75%

Section: Introductionmentioning

confidence: 93%

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Standard molar enthalpy of formation of rubidium diphosphate

Khaled

Khattech

Jemal

2014

J Therm Anal Calorim

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“…Meadowcroft and Richardson measured the enthalpies of formation of Li 3 PO 4 , Li 4 P 2 O 7 , and Li 5 P 3 O 10 using solution calorimetry, and their impurities of starting materials have been studied by chromatographic methods. Recently, acid solution calorimetry was performed by Gmati‐Ben Khaled et al to measure the enthalpy of formation of Li 4 P 2 O 7 compounds at 298 K. The calculated enthalpies of formation of the compounds are shown in Figure with the experimental data . The thermodynamic descriptions for Li 3 PO 4 , LiPO 3 , and Li 4 P 2 O 7 are the same as those in the FToxide database …”

Section: Thermodynamic Assessment and Optimizationmentioning

confidence: 99%

Experimental and thermodynamic study of Li‐O and Li₂O‐P₂O₅ systems

et al. 2019

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LiFePO 4 (LFP) as a promising cathode material has been extensively studied. However, the high cost of current batch production technology limits its application, especially in automotive industries. To develop the new melting synthesis of LFP, the process conditions have to be strictly controlled, such as temperature, composition, and the partial pressure of oxygen. Reliable and accurate thermodynamic information about Li-Fe-P-O systems could serve as a useful guide for designing operating conditions. As part of ongoing efforts, the Li-O and Li 2 O-P 2 O 5 binary systems have been first studied following the CALPHAD method using FactSage thermodynamic software. The data on thermodynamic properties (C p , enthalpy of formation, and vapour pressure) and phase diagrams (liquidus/solidus temperature, phase transition, and solid solubility) available in the literature were carefully reviewed and evaluated for the above-mentioned systems. The modified quasichemical model (MQM) with quadruplet approximation was used for the liquid phase in the present studies. This model simultaneously takes into account the short-range ordering of firstnearest-neighbours (FNN) and second-nearest-neighbours (SNN), which improves the thermodynamic description of the Gibbs energy of the liquid. The thermodynamic model parameters of the Gibbs energy have been obtained for all of the phases considered in the Li-O and Li 2 O-P 2 O 5 binary systems. DSC-TGA experiments on the selected four compositions were carried out to validate the liquidus and phase transition temperature reported in the literature. Overall, the self-consistent thermodynamic description using the model parameters obtained in this work can successfully reproduce the evaluated experimental data.

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“…After a stabilization time of 12 h, the reactants were mixed using the reversing mechanism which allows the calorimeter jacket to be alternatively in the reversal then the upward position [26,[35][36][37][38]].…”

Section: Thermochemical Studymentioning

confidence: 99%

Standard Formation Enthalpy of Na2O–ZnO–P2O5 Series Glasses

2018

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100 − x)NaPO 3 -xZnO (0 ≤ x ≤ 33 mol%) phosphate glasses have been prepared using the conventional melt quenching technique. Amorphous state was checked up by X-ray diffraction. Glasses have been investigated in detail by mean of differential scanning calorimetry, inductively coupled plasma. Incorporation of ZnO oxide increases the T g value and the thermal stability of samples. For this glass series, 31 P solid state magic angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopy revealed the decrease of Q 2 tetrahedral sites and the increase of phosphate dimers (Q 1 ), when ZnO oxide is progressively introduced, suggesting the shortening of metaphosphate chains. Dissolution of glasses has been followed calorimetrically and showed a change in thermal signs resulting from the depolymerization of metaphosphate groups when ZnO oxide is added. A thermochemical cycle involving a number of dissolution and mixing processes have been carried out in order to get the standard enthalpy of formation of these glasses. Calculation of these quantities needs the standard enthalpy of formation of sodium trimetaphosphate. Formation enthalpy of glasses increases with the incorporation of ZnO oxide.

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Standard enthalpy of formation of lithium diphosphate

Cited by 8 publications

References 11 publications

Standard molar enthalpy of formation of rubidium diphosphate

Standard molar enthalpy of formation of rubidium diphosphate

Experimental and thermodynamic study of Li‐O and Li₂O‐P₂O₅ systems

Standard Formation Enthalpy of Na2O–ZnO–P2O5 Series Glasses

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Standard enthalpy of formation of lithium diphosphate

Cited by 8 publications

References 11 publications

Standard molar enthalpy of formation of rubidium diphosphate

Standard molar enthalpy of formation of rubidium diphosphate

Experimental and thermodynamic study of Li‐O and Li2O‐P2O5 systems

Standard Formation Enthalpy of Na2O–ZnO–P2O5 Series Glasses

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Experimental and thermodynamic study of Li‐O and Li₂O‐P₂O₅ systems