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Ca3(VO4)2 is a promising candidate for applications in ferroelectric, laser host, and optical materials owing to its unique whitlockite structure and excellent physicochemical properties. In this study, the Ca3(VO4)2 powder was fabricated via a conventional solid‐phase route in air, using V2O5 and CaO as precursors. The trigonal Ca3(VO4)2 belongs to the space group R3c, having unit cell parameters of a = 10.8074 Å, b = 10.8074 Å, and c = 37.98871 Å, respectively. Ca3(VO4)2 melts congruently at 1680 K, as determined from differential scanning calorimetry measurements of the thermal profile of the second heating test. Enthalpy changes in Ca3(VO4)2 were experimentally determined for the first time across temperatures between 573 and 1623 K by drop calorimetry. The temperature‐dependent molar heat capacity of Ca3(VO4)2 was calculated from the enthalpy changes at elevated temperatures. Thermodynamic properties (entropy, enthalpy, and Gibbs free energy changes) were also calculated. The thermodynamic properties measured in this study were further applied to evaluate the appropriate precursors for fabricating Ca3(VO4)2 via solid‐state calcination. The results strongly recommend the use of V2O5 and Ca(OH)2 precursors for preparing the Ca3(VO4)2 samples because of their thermodynamic advantages. [ABSTRACT FROM AUTHOR]

A Ca5Mg4V6O24 compound was synthesized through solid‐state roasting routes under an air atmosphere, and its crystal structure and thermodynamic properties were determined using various methods. The cell parameters of Ca5Mg4V6O24 indicate that it crystallizes in cubic space group Ia3d with the unit cell parameters a = 12.442 ± 0.001 Å. X‐ray photoelectron spectroscopy also confirmed that the vanadium element in the Ca5Mg4V6O24 sample is present in the +5 state. The melting of Ca5Mg4V6O24 was detected at 1442 K. The molar heat capacity (374 J mol K−1) and entropy (688.2 J mol K−1) of Ca5Mg4V6O24 at 298.15 K were determined using physical properties measurement system, and simultaneous thermal analyzer for the first time. The solubility of Ca5Mg4V6O24 in water at different temperatures was measured and its dissolution behavior in sulfuric acid and kinetics was experimentally established. [ABSTRACT FROM AUTHOR]

High-purity Na8Ti5O14 was synthesized using Na2CO3 and TiO2 as the starting materials by a solid-phase reaction. Heat capacity of Na8Ti5O14 was measured by PPMS at low temperatures and MHTC 96 line at high temperatures. The changes in enthalpy at 298.15 K were Δ 0 298.15 K H m = 95.43 kJ mol−1, and standard molar entropy was S m θ = 569.35 J\,mol−1\,K−1, respectively. The changes in enthalpy ( Δ 298.15 T m H m ), entropy ( Δ 298.15 T m S m ), and Gibbs energy ( Δ 298.15 T m G m ) from (298.15 to 1303) K were calculated using heat capacity functions. [ABSTRACT FROM AUTHOR]

Andradite titanium (Ca3Fe2Si1.58Ti1.42O12, abbreviated as AT), which is a significant mineral phase in the sinter of titanium‐containing iron ore, was prepared via a solid‐state reaction with analytical reagents. The crystal structure, cold strength, and high‐temperature heat capacity were individually characterized, and the metallurgical performance, such as melting and reduction behavior, were measured. AT is a variant of andradite (Ca3Fe2Si3O12) formed by the Ti4+ substitution for Fe3+ in the octahedral sites and Fe3+ substitution for Si4+ in the tetrahedral sites. The compressive strength of AT was approximately 14.21 MPa, and its softening, melting, and flowing temperatures were 1453, 1483, and 1509 K, respectively. According to the differential scanning calorimetry measurements, the melting point was approximately 1502 K. The non‐isothermal reduction results revealed that AT was reduced to Fe, perovskite, and wollastonite in a single step, and the isothermal reduction test indicated that the reduction degree of AT was only 0.67 when reduced at 900°C for 150 min, and the order of reduction performance was Fe2O3 > Fe3O4 > CaO·2Fe2O3 > CaO·Fe2O3 > 2CaO·Fe2O3 > AT. The high‐temperature heat capacity of AT as a function of temperature was also measured and modeled. [ABSTRACT FROM AUTHOR]

Sodium‐ion batteries (NaIBs) have attracted extraordinary attentions as a promising scalable energy storage alternative to current lithium‐ion batteries (LIBs), owing to their natural abundance and low costs. Sodium trititanate (Na2Ti3O7) is a promising material as the material of NaIBs with low potential and high theoretical capacitance. In order to better understand their service performance when utilized in rechargeable NaIBs, studies on thermodynamic properties of Na2Ti3O7 are indispensable. However, an extensive literature review revealed that the heat capacity of Na2Ti3O7 is established with divergences, especially for high‐temperature region. Therefore, the 99.5% purity of Na2Ti3O7 powder was first Synthesized through solid‐state reaction with sodium carbonate (Na2CO3) and titanium dioxide (TiO2) as raw materials. The as‐prepared samples were used to measure the heat capacity from 573 to 1323 K which was carried out with multihigh temperature calorimeter (MHTC) 96 line. The temperature dependence of heat capacity was modeled as a function: Cp =255.51073 + 0.06059 T − 3.86912 × 106 T−2 (J mol−1 K−1) (298.15 ‐ 1403 K), and then used for computing changes in enthalpy, entropy, and Gibbs free energy. Heat capacity of Na2Ti3O7 from 0 to 1403 K was given for future application of Na2Ti3O7 in rechargeable batteries. [ABSTRACT FROM AUTHOR]

Ca3(VO4)2 is a promising candidate for applications in ferroelectric, laser host, and optical materials owing to its unique whitlockite structure and excellent physicochemical properties. In this study, the Ca3(VO4)2 powder was fabricated via a conventional solid‐phase route in air, using V2O5 and CaO as precursors. The trigonal Ca3(VO4)2 belongs to the space group R3c, having unit cell parameters of a = 10.8074 Å, b = 10.8074 Å, and c = 37.98871 Å, respectively. Ca3(VO4)2 melts congruently at 1680 K, as determined from differential scanning calorimetry measurements of the thermal profile of the second heating test. Enthalpy changes in Ca3(VO4)2 were experimentally determined for the first time across temperatures between 573 and 1623 K by drop calorimetry. The temperature‐dependent molar heat capacity of Ca3(VO4)2 was calculated from the enthalpy changes at elevated temperatures. Thermodynamic properties (entropy, enthalpy, and Gibbs free energy changes) were also calculated. The thermodynamic properties measured in this study were further applied to evaluate the appropriate precursors for fabricating Ca3(VO4)2 via solid‐state calcination. The results strongly recommend the use of V2O5 and Ca(OH)2 precursors for preparing the Ca3(VO4)2 samples because of their thermodynamic advantages. [ABSTRACT FROM AUTHOR]

The high-temperature heat capacity of sodium metavanadate (NaVO 3) was measured using a differential scanning calorimeter (DSC) for temperature in the 303–573 K range, and using a multi-high temperature calorimeter 96 line for temperature in the 323–773 K range. The obtained high-temperature heat capacity of NaVO 3 , as a function of temperature, was modeled as: Cp = 22.08251 + 0.3449T-3.32185 × 10 −4 T 2 + 9.76468 × 10 −8 T 3 (298.15-773 K). The temperature dependence of the heat capacity was then used for computing changes in the enthalpy, entropy, and Gibbs free energy. The non-isothermal kinetics of the solid-solid phase transformation of NaVO 3 were examined by using various DSC curves. The findings indicate that the reaction mechanism of the solid-solid phase transformation of NaVO 3 includes two stages, the first of which is controlled by a fibril-like mechanism, while the second is controlled by a disc-type mechanism. In the present study, the apparent activation energy of the solid-solid phase transformation of NaVO 3 , which was calculated using the Kissinger method and the Ozawa method, was equal to 628 ± 14 kJ·mol −1 and 610 ± 12 kJ·mol −1 , respectively. • The high-temperature heat capacity was measured in the temperature ranging 303–770 K. • Other thermodynamic functions were calculated from the fitted heat capacity equations. • Reaction mechanism and activation energy are confirmed by thermal analysis kinetics. [ABSTRACT FROM AUTHOR]

A Ca5Mg4V6O24 compound was synthesized through solid‐state roasting routes under an air atmosphere, and its crystal structure and thermodynamic properties were determined using various methods. The cell parameters of Ca5Mg4V6O24 indicate that it crystallizes in cubic space group Ia3d with the unit cell parameters a = 12.442 ± 0.001 Å. X‐ray photoelectron spectroscopy also confirmed that the vanadium element in the Ca5Mg4V6O24 sample is present in the +5 state. The melting of Ca5Mg4V6O24 was detected at 1442 K. The molar heat capacity (374 J mol K−1) and entropy (688.2 J mol K−1) of Ca5Mg4V6O24 at 298.15 K were determined using physical properties measurement system, and simultaneous thermal analyzer for the first time. The solubility of Ca5Mg4V6O24 in water at different temperatures was measured and its dissolution behavior in sulfuric acid and kinetics was experimentally established. [ABSTRACT FROM AUTHOR]

High-purity Na8Ti5O14 was synthesized using Na2CO3 and TiO2 as the starting materials by a solid-phase reaction. Heat capacity of Na8Ti5O14 was measured by PPMS at low temperatures and MHTC 96 line at high temperatures. The changes in enthalpy at 298.15 K were Δ 0 298.15 K H m = 95.43 kJ mol−1, and standard molar entropy was S m θ = 569.35 J\,mol−1\,K−1, respectively. The changes in enthalpy ( Δ 298.15 T m H m ), entropy ( Δ 298.15 T m S m ), and Gibbs energy ( Δ 298.15 T m G m ) from (298.15 to 1303) K were calculated using heat capacity functions. [ABSTRACT FROM AUTHOR]

MnV 2 O 6 and Mn 2 V 2 O 7 are the key compounds during the manganese salt roasting for extracting vanadium from vanadium bearing slag. Thermodynamic properties of MnV 2 O 6 and Mn 2 V 2 O 7 are dispensable to get insight into the multi-phase reaction mechanism and clarify the phase evolution. In this study, the MnV 2 O 6 and Mn 2 V 2 O 7 compounds were synthesized through solid-state roasting routes under a nitrogen gas atmosphere, and their crystal structure and thermodynamic properties were determined using X-ray powder diffraction, differential scanning calorimetry, and drop calorimetry. The enthalpy increments of MnV 2 O 6 and Mn 2 V 2 O 7 were experimentally measured for temperatures ranging from 573 K to 1023 K and 573 K to 1173 K, respectively, using drop calorimetry for the first time. Based on the experimentally measured enthalpy increments, the temperature dependence of the molar heat capacity of MnV 2 O 6 and Mn 2 V 2 O 7 was then derived. Furthermore, thermodynamic properties such as enthalpy, entropy, and Gibbs free energy were also calculated. Finally, the Gibbs free energy of the chemical reactions during the roasting of vanadium slag was evaluated, and compared with other roasting techniques. • The high purity of MnV 2 O 6 and Mn 2 V 2 O 7 were prepared through solid-state roasting routes under a nitrogen gas atmosphere. • The enthalpy increments of MnV 2 O 6 and Mn 2 V 2 O 7 were experimentally measured using drop calorimetry. • Thermodynamic properties of MnV 2 O 6 and Mn 2 V 2 O 7 such as the enthalpy, entropy, and Gibbs free energy were calculated. • Gibbs free energy of the roasting reactions of vanadium slag were calculated and compared. [ABSTRACT FROM AUTHOR]

Sodium-ion batteries have emerged as a promising alternative to lithium-ion batteries due to their lower cost and similar electrochemical properties. The development of high-capacity and long-life electrode materials is crucial for advancing sodium-ion battery research. A significant amount of research has been conducted on the electrochemical properties of NaV 6 O 15 , however, there remains a dearth of data on its thermodynamic properties. Herein, NaV 6 O 15 was synthesized using the solid-phase sintering method and thoroughly characterized. Thermodynamic data in the temperature ranges of 298.15–900 K, 15–303 K, and 573–873 K were determined using the Neumann-Kopp rule, low-temperature physical property measurement system, and MHTC 96 line, respectively. The heat capacity equation of NaV 6 O 15 was derived and its enthalpy, entropy, and Gibbs free energy (298.15–800 K) were calculated. Moreover, the thermodynamics of NaV 6 O 15 -related formation and decomposition reactions were analyzed. The obtained heat capacity equation of NaV 6 O 15 was C p = 517.05524 + 0.08612 T − 1.25053 × 1 0 7 T − 2 (J / m o l · K) (298.15 ∼ 873 K). This study addresses the thermodynamic knowledge gaps of NaV 6 O 15 and provides valuable insights for its preparation and decomposition in manufacturing processes. • The heat capacity equation of the self-synthesized NaV 6 O 15 were obtained by PPMS, NKR, and drop methods. • The thermodynamic parameters of NaV 6 O 15 were calculated by the heat capacity equation. • Thermodynamic analysis of NaV 6 O 15 -related reactions using experimental data. [ABSTRACT FROM AUTHOR]

CaV 2 O 6 is widely utilized in optoelectronic materials, dielectric ceramics, magnetic candidates, and catalytic materials due to its unique physical and chemical properties. CaV 2 O 6 was synthesized by a conventional solid-state reaction technique in this study. The CaV 2 O 6 crystallizes in a monoclinic system belonging to space group C 2/ m , with the lattice parameters of a = 10.06 Å, b = 3.675 Å, c = 7.039 Å, and β = 104.843°. The congruent melting of CaV 2 O 6 was detected at 1045 K by performing DSC. Enthalpy increments of CaV 2 O 6 were experimentally measured for temperatures ranging from 573 K to 1023 K employing drop calorimetry for the first time. The temperature dependence of the molar heat capacity of CaV 2 O 6 was then calculated on the basis of the enthalpy increments results. Thermodynamic properties (enthalpy change, entropy, and Gibbs free energy) were also calculated in the temperature range of 300–1000 K. [ABSTRACT FROM AUTHOR]

Sodium hexatitanate (Na 2 Ti 6 O 13) was reported as an anode side material for Sodium ion batteries owing to low material cost, high energy efficiency, good thermal stability and long cycle life. Therefore, studies pertaining to the thermodynamic properties of Na 2 Ti 6 O 13 are indispensable for improving its service performance. However, a significant number of literature reviews concerning thermodynamic properties indicated that heat capacity of Na 2 Ti 6 O 13 at high temperatures should be confirmed. In this study, the 99.5% purity of Na 2 Ti 6 O 13 sample was successfully prepared via solid-state reaction using TiO 2 and Na 2 CO 3 as initial materials. Heat capacity of the as-synthesized samples in the temperature range of 573–1523 K was measured using a multi-high temperature calorimeter 96 line. Heat capacity, Cp, from 298.15 to 1573 K was modeled as a polynomial formula with a prediction error of 3%: Cp = 474.08143 + 0.06286T-8.04068 × 106 T−2 (J⋅mol−1⋅K−1). In combination with the low-temperature data, heat capacity of Na 2 Ti 6 O 13 from 0 to 1573 K was given in present study. Values of changes in enthalpy, Gibbs free energy and entropy in the temperature range of 298.15–1573 K were calculated based on the temperature dependence of heat capacity. [ABSTRACT FROM AUTHOR]

Mg 3 (VO 4) 2 powder was synthesized via a simple solid-state reaction under air atmosphere, and X-ray diffraction was employed to investigate the cell parameters of the as-prepared powder. The cell parameters indicated that the sample was crystallized in the form of Cmca orthorhombic system with lattice parameters, a = 6.053 Å, b = 11.442 Å, and c = 8.330 Å. The high-temperature enthalpy changes in Mg 3 (VO 4) 2 were measured in the range of 573–1473 K by drop calorimetry for the first time. Furthermore, the temperature dependence of the heat capacity of Mg 3 (VO 4) 2 was calculated by considering the enthalpy changes results. Thermodynamic properties (changes in enthalpy, entropy, and Gibbs free energy) were also calculated in the range of 298.15–1473 K. [ABSTRACT FROM AUTHOR]

The sodium pyrovanadate (Na 4 V 2 O 7) powder was synthesized by solid-state reaction using sodium carbonate (Na 2 CO 3) and vanadium pentoxide (V 2 O 5) as raw materials. X-ray powder diffraction (XRD), scanning electron microscope (SEM), and differential scanning calorimeter (DSC) were used to accurately characterize the synthesized sample. The solid-state phase transformation from α-Na 4 V 2 O 7 to β-Na 4 V 2 O 7 occurs at the temperature 696 K and the enthalpy is equals to 1.03 ± 0.01 kJ/mol, the endothermic effect at 931 K and the enthalpy is equals to 31.35 ± 0.31 kJ/mol, which is related to the melting of Na 4 V 2 O 7. The high-temperature heat capacity of Na 4 V 2 O 7 was measured using a Multi-high temperature calorimeter 96 line and DSC. The obtained high-temperature heat capacity of Na 4 V 2 O 7 , as a function of temperature, was modeled as: Cp=314.62 + 0.05T- 5494390T-2 J·mol-1·K-1 (298.15-873 K). The temperature dependence on heat capacity was then used for computing changes in the enthalpy, entropy, and Gibbs free energy at the specific temperature internal. • Temperature and heats of phase transformation of Na 4 V 2 O 7 was measured by DSC. • High-temperature heat capacity was measured using Drop calorimeter. • Other thermodynamic functions were calculated from the heat capacity equations. [ABSTRACT FROM AUTHOR]