The Heat Capacity of Nickel Oxide from 68-298°K. and the Thermodynamic Properties of the Oxide

Seltz, Harry; DeWitt, B. J.; McDonald, Hugh J.

doi:10.1021/ja01858a022

Cited by 24 publications

(12 citation statements)

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“…2 with the measured zero pressure values. 35,36 For MnO, the experimental peak below 150 K is due to the magnetic Néel phase transition 36 ͑T N = 118 K͒ which is not considered in the present work. The deviation between the present theory and the measurement for NiO above 200 K is also due to neglecting the magnetic contribution in the present work ͓the experimental T N of NiO is 523 K ͑Ref.…”

Section: ͑2͒mentioning

confidence: 87%

Broken symmetry, strong correlation, and splitting between longitudinal and transverse optical phonons of MnO and NiO from first principles

et al. 2010

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We propose a first-principles scheme, using the distorted structure, to obtain the phonons of the undistorted parent structure for systems with both broken symmetry as well as the splitting between longitudinal optical and transverse optical ͑TO͒ phonon modes due to long-range dipole-dipole interactions. Broken symmetry may result from antiferromagnetic ordering or structural distortion. Applications to the calculations of the phonon dispersions of NiO and MnO, the two benchmark Mott-Hubbard systems with the TO mode splitting for MnO, show remarkable accuracy.With advances in calculating atomic force constants within the framework of density-functional perturbation theory 1 and density-functional theory, 2 first-principles calculations can now predict electronic and vibrational properties for many classes of materials, including simple metals, transition metals, intermetallics, semiconductors, hydrides, and earth materials with exceptional accuracy. 3 However, it has been difficult to predict the lattice dynamics for strongly correlated electronic systems, particularly Mott-Hubbard insulators. These include materials such as NiO and MnO, 4-8 the La 2 CuO 4 -based cuprate superconductors, 9 and the LaMnO 3 -based colossal magnetoresistance manganites. 10 Experimental measurements also yielded inconsistent results on the frequency values of the optical phonons for both MnO ͑Refs. 6 and 8͒ and NiO. 5,7 The specific difficulties 11-15 in predicting the lattice dynamics of Mott-Hubbard insulators are: ͑i͒ the highly correlated nature of electronic states in these materials and ͑ii͒ the slight lowering of crystal symmetry as a result of antiferromagnetic ordering ͑ϳ0.6°for MnO and ϳ0.07°for NiO away from cubic 16 ͒.In this work, we report a scheme to accurately compute phonon dispersions of Mott-Hubbard systems such as MnO and NiO. This involves a combination of a method for recovering the ideal cubic symmetry from the slightly distorted structure, the mixed-space approach 17 for treating the splitting between longitudinal optical ͑LO͒ and transverse optical ͑TO͒ phonon modes, and the density-functional theory ͑DFT͒ plus U method for accounting for the strong electron correlation. 18 In applying the direct approach to predict the phonon dispersions of polar materials, a lot of effort 19-23 has been made to treat the contribution of the nonanalytical term. The mixed-space approach makes it parameter-free to accurately determine the phonon frequencies using the direct approach for polar materials. 17 In this approach, the force constants are written aswhere ⌽ ␣␤ jk is the interaction force-constant between atom j in the primitive cell M and atom k in the primitive cell P, ␣␤ jk the contribution from short-range interactions, N the number of primitive unit cells in the supercell, and D ␣␤ jk ͑na ; q → 0͒ the contribution from long-range interactions, i.e., the so-called nonanalytical part of the dynamical matrix in the limit of zero wave vector q. According to Cochran and Cowley 24

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Section: ͑2͒mentioning

confidence: 87%

Broken symmetry, strong correlation, and splitting between longitudinal and transverse optical phonons of MnO and NiO from first principles

et al. 2010

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“…The resulting values for the energy changes of reactions E3-E6 are reported in Table 3 for all the polymorphs of the LCO, LMO and LNO compounds. The ∆E values reported in the Table 4 can be easily combined with literature thermochemical data [54][55][56][57][58][59][60][61] reported in the Supplementary Material (Table S2) to derive the formation energy from elements (Table S3). To derive the formation thermodynamics at room temperature, thermal effects and formation entropies at 298 K are necessary.…”

Section: Discussionmentioning

confidence: 99%

Analysis of the Phase Stability of LiMO2 Layered Oxides (M = Co, Mn, Ni)

Tuccillo¹,

Palumbo²,

Pavone

et al. 2020

Crystals

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Transition-metal (TM) layered oxides have been attracting enormous interests in recent decades because of their excellent functional properties as positive electrode materials in lithium-ion batteries. In particular LiCoO2 (LCO), LiNiO2 (LNO) and LiMnO2 (LMO) are the structural prototypes of a large family of complex compounds with similar layered structures incorporating mixtures of transition metals. Here, we present a comparative study on the phase stability of LCO, LMO and LNO by means of first-principles calculations, considering three different lattices for all oxides, i.e., rhombohedral (hR12), monoclinic (mC8) and orthorhombic (oP8). We provide a detailed analysis—at the same level of theory—on geometry, electronic and magnetic structures for all the three systems in their competitive structural arrangements. In particular, we report the thermodynamics of formation for all ground state and metastable phases of the three compounds for the first time. The final Gibbs Energy of Formation values at 298 K from elements are: LCO(hR12) −672 ± 8 kJ mol−1; LCO(mC8) −655 ± 8 kJ mol−1; LCO(oP8) −607 ± 8 kJ mol−1; LNO(hR12) −548 ± 8 kJ mol−1; LNO(mC8) −557 ± 8 kJ mol−1; LNO(oP8) −548 ± 8 kJ mol−1; LMO(hR12) −765 ± 10 kJ mol−1; LMO(mC8) −779 ± 10 kJ mol−1; LMO(oP8) −780 ± 10 kJ mol−1. These values are of fundamental importance for the implementation of reliable multi-phase thermodynamic modelling of complex multi-TM layered oxide systems and for the understanding of thermodynamically driven structural phase degradations in real applications such as lithium-ion batteries.

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“…Substituting and differentiating, S = R In _k/~ + R [24] Change of entropy of the NiO lattice due to distortion caused by presence of vacancies and positive holes is given by the relation S = R In vv [25] VN Here, VD refers to the frequency of vibration in the disturbed state and vN to the normal state. Frequencies are calculated from the equation…”

Section: Entropy Of Formation Of a Cation Vacancy--entropymentioning

confidence: 99%

The Kinetics of Oxidation of High Purity Nickel

Gulbransen

Andrew

1954

J. Electrochem. Soc.

100

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The effect of time, temperature, and surface pretreatment on rate of oxidation of high purity nickel is studied for the temperature range of 400~176 using a vacuum microbalance technique. The data are compared to previous studies in the literature and with other metals. Oxidation data are interpreted in terms of the parabolic rate law and classical theory of diffusion.Large deviations from the parabolic rate law are found to occur during the initial stages of reaction and smaller deviations over long periods of time, especially at low temperatures. However, reasonable values of heat and entropy of activation for the over-all reaction can be calculated; these are 41,200 cal/mole and -6.0 entropy units (eu), respectively. Parabolic rate law constants over the temperature range of 550 ~ 700~ are given by A = 3.8 X l~4e-41'~~The negative value for entropy of activation for the over-all reaction when corrected for entropy of formation of the vacancies leads to a value of 1.5 for entropy of activation for diffusion. Theoretical considerations suggest that the latter term should have a value of 1.7-3.3 eu. The good agreement between theoretical and experimental entropies of activation suggests that diffusion is occurring largely through the lattice of nickel oxide and not at grain boundaries, at least for the temperature and time region over which analyses were made.A comparison of present data with older studies in the literature shows a large variation in parabolic rate law constants. These variations are interpreted in terms of impurities increasing the concentration of nickel ion vacancies, KINETICS OF OXIDATION OF NICKEL 131

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The Heat Capacity of Nickel Oxide from 68-298°K. and the Thermodynamic Properties of the Oxide

Cited by 24 publications

References 0 publications

Broken symmetry, strong correlation, and splitting between longitudinal and transverse optical phonons of MnO and NiO from first principles

Broken symmetry, strong correlation, and splitting between longitudinal and transverse optical phonons of MnO and NiO from first principles

Analysis of the Phase Stability of LiMO2 Layered Oxides (M = Co, Mn, Ni)

The Kinetics of Oxidation of High Purity Nickel

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