Heat capacity and thermodynamic functions of transition metal ion (Cu2+, Fe2+, Mn2+) exchanged, partially dehydrated zeolite A (LTA)

Dickson, Matthew S.; Rosen, Peter F.; Neilsen, Grace; Navrotsky, Alexandra; Woodfield, Brian F.

doi:10.1016/j.jct.2021.106556

Cited by 5 publications

(3 citation statements)

References 15 publications

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“…Because n sch increases with increasing water content in these samples (Table 4), interactions in the interlayer between the water, hydroxyl groups, and anions are likely sources of the Schottky anomaly. Schottky anomalies are commonly seen in the heat capacities of paramagnetic salts due to the splitting of electronic spin states 31,32 or in compounds containing nuclei with non-zero nuclear spin being split by local magnetic fields. 33,34 However, we do not expect these phenomena in [Zn−Al−X] LDHs, so there is apparently some other two-level system in these samples.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Role of Anions in Stabilizing the [Zn–Al] Layered Double Hydroxides: A Thermodynamic Study

et al. 2023

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Room-temperature acid solution calorimetry, high-temperature oxide melt solution calorimetry, and low-temperature heat capacity measurements were employed to calculate the thermodynamic stabilities of the [Zn–Al–X] layered double hydroxides (LDH) containing different anions (X = Cl–, CO3 2–, and SO4 2–). Cryogenic heat capacity measurements demonstrated a Schottky-type anomaly in the heat capacity of all three LDHs below 11 K. This anomaly is attributed to the tunneling of protons between adjacent oxygen atoms in the LDH interlayer as this creates an energy system similar to a two-level system modeled with a Schottky term. These heat capacity measurements were also used to determine vibrational entropies which, when combined with configurational entropies, provide standard entropies of these LDHs. Enthalpies of formation of LDHs from binary components were determined and combined with the entropies of formation to calculate Gibbs free energies. Based on these values, the order of stability is [Zn–Al–SO4] > [Zn–Al–CO3] > [Zn–Al–Cl]. This trend results from a combination of the interlayer spacing, amount of water in the interlayer, interactions among the interlayer species, and interactions between the metal hydroxide layer and the interlayer.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Role of Anions in Stabilizing the [Zn–Al] Layered Double Hydroxides: A Thermodynamic Study

et al. 2023

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“…Therefore, the low-temperature fitting parameters, particularly those for the lattice and antiferromagnetic heat capacity, have relatively limited physical significance, but the thermodynamic data calculated from these fittings are valid. In addition, Compound 3 has a much higher γ value (1.3445 J·mol −1 ·K −2 ) than Compounds 1 and 2 , which could be explained by the significant electronic contribution of Cu 2+ at low temperatures, leading to the apparent Schottky anomaly [ 27 ].…”

Section: Resultsmentioning

confidence: 99%

“…For example, the entropy gain at phase transition is a diagnostic metric for understanding the chaotic changes of the system [ 22 ]. Based on the above fitting and basic thermodynamic laws, the standard thermodynamic functions of Compounds 1 – 3 were calculated [ 26 , 27 ], and the results are presented in Table S5 . The standard molar heat capacity, entropy and enthalpy at 298.15 K and 0.1 MPa were determined to be

= (793.4 ± 7.9), (776.7 ± 7.8) and (774.0 ± 7.7) J·K −1 ·mol −1 ;

= (836.4 ± 8.4), (821.1 ± 8.2) and (838.4 ± 8.4) J·K −1 ·mol −1 ; and

= (126.3 ± 1.3), (123.9 ± 1.2) and (123.5 ± 1.2) kJ·mol −1 for Compounds 1 , 2 and 3 , respectively.…”

Section: Resultsmentioning

confidence: 99%

Magnetic Property, Heat Capacity and Crystal Structure of Mononuclear Compounds Based on Substitute Tetrazole Ligand

Zheng,

Luo,

Wang

et al. 2023

Molecules

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Three mononuclear compounds formulated as {M[(2-1H-tetrazol-5-yl)pyridine]2(H2O)2} (M = FeII (1), CoII (2), CuII (3)) were reported and synthesized. Their space group is monoclinic, P21/c, revealed by single-crystal X-ray diffraction. Antiferromagnetic interactions exist in Compounds 1, 2 and 3, as evidenced by magnetic and low-temperature heat capacity measurements. In addition, their thermodynamic functions were determined by a relaxation calorimeter, indicating that Compound 1 exhibits a Schottky anomaly in low-temperature heat capacity. This work can provide an important fundamental basis for the research of the thermophysical properties of molecular-based magnetic materials.

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The low-temperature heat capacity and thermodynamic properties of greigite (Fe3S4)

Shumway

Wilson²,

Lilova³

et al. 2022

The Journal of Chemical Thermodynamics

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Heat capacity and thermodynamic functions of transition metal ion (Cu2+, Fe2+, Mn2+) exchanged, partially dehydrated zeolite A (LTA)

Cited by 5 publications

References 15 publications

Role of Anions in Stabilizing the [Zn–Al] Layered Double Hydroxides: A Thermodynamic Study

Role of Anions in Stabilizing the [Zn–Al] Layered Double Hydroxides: A Thermodynamic Study

Magnetic Property, Heat Capacity and Crystal Structure of Mononuclear Compounds Based on Substitute Tetrazole Ligand

The low-temperature heat capacity and thermodynamic properties of greigite (Fe3S4)

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