Selected values of chemical thermodynamic properties :

Schumm, Richard H.; Wagman, Donald D.; Bailey, S M; Evans, W. H.; Parker, V. B.

doi:10.6028/nbs.tn.270-6

Cited by 77 publications

(99 citation statements)

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“…The CC bond length of relaxed structure of each model sample of graphene is 1.42 Å and the NN bond length of an isolated nitrogen molecule is 1.11 Å which are in agreement with the available data . The cohesive energy of each model sample is found to be 8.05 eV/atom, in close agreement with the previous theoretical and experimental values of 8.57 and 7.39 eV, respectively. We find the bond energy of each model sample of graphene as 5.37 eV, in good agreement with the previous value of 4.93 eV.…”

Section: Resultssupporting

confidence: 90%

A first principle study of adsorption of two proximate nitrogen atoms on graphene

Rani

Dharamvir

2014

Int J of Quantum Chemistry

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Different possible configurations of two nitrogen‐adatoms on graphene are studied using density functional theory. Adsorption of single nitrogen atom on the bridge site of graphene is accompanied by distortion of the sheet. Electronically, this case amounts to p‐type doping. Two N atoms adsorbed on the graphene sheet can share a bond in two ways. They acquire positions either just above two adjacent carbon atoms or they form a bridge across opposite bonds of a hexagon in the sheet. Both these configurations also induce structural distortion of the sheet. Another stable configuration consists of two N atoms bonded as an N2 molecule physisorbed on the graphene sheet. It is also possible to adsorb two N atoms on opposite sides of the graphene sheet, bonded to the same two C atoms. Moreover, two N atoms can be individually adsorbed on alternate bridge sites of neighboring hexagons experiencing a repulsion, the energy for which arises from the additional distortion of the graphene sheet. The densities of states near the Fermi level are found to be dependent on the adsorption configurations of two nitrogen atoms on graphene. Thus the electronic properties of graphene can be controlled by the selective adsorption of two nitrogen atoms. © 2014 Wiley Periodicals, Inc.

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Section: Resultssupporting

confidence: 90%

A first principle study of adsorption of two proximate nitrogen atoms on graphene

Rani

Dharamvir

2014

Int J of Quantum Chemistry

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“…The calculated values in this work are in consistent with the available experimental data in Ref. 37,38 Because of different approximation method resulting in calculation accuracy, the values are a little difference with the values obtained by Hui Zhang et al 28 , and in Ref. 28,37,38 the enthalpy of formation is expressed as kJ/mol, we calculated the enthalpy of formation expresses as eV/atom.…”

Section: Methods and Detailssupporting

confidence: 87%

“…37,38 Because of different approximation method resulting in calculation accuracy, the values are a little difference with the values obtained by Hui Zhang et al 28 , and in Ref. 28,37,38 the enthalpy of formation is expressed as kJ/mol, we calculated the enthalpy of formation expresses as eV/atom. The stability of these compounds forms the following sequence: GaMg> O-Ga 2 Mg > H-Ga 2 Mg > Ga 5 Mg 2 > GaMg 2 > Ga 2 Mg 5 .…”

Section: Methods and Detailsmentioning

confidence: 89%

Stability, Mechanical Properties and Anisotropic Elastic Properties of GaxMgy Compounds

Liu¹,

Lian²,

2019

Mat. Res.

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The stability, mechanical properties and anisotropic properties of sound velocities of Ga 2 Mg 5 , GaMg 2 , GaMg, O-Ga 2 Mg, H-Ga 2 Mg and Ga 5 Mg 2 are investigated systematically by the first-principles calculation. The cohesive energy and formation enthalpy are obtained and used to estimate the stability of the Ga-Mg binary compounds. GaMg compound is the most stable and has the lowest formation enthalpy as -0.162eV/atom of those Ga x Mg y compounds. The elastic constants of single crystal, hardness, bulk, shear, Young's modulus and Poisson's ratio of the polycrystalline crystal are obtained and used to estimate the mechanical properties. Ga 5 Mg 2 and H-Ga 2 Mg have the lager bulk, shear and Young's modulus and corresponding B/G is low. H-Ga 2 Mg is harder than the other compounds from the results of Poisson's ratio. The anisotropic mechanical properties are discussed using the anisotropic index, two-dimensional planar projections on different planes of the bulk and Young's modulus. The Young's modulus of H-Ga 2 Mg shows the strongly anisotropy of mechanical properties and GaMg 2 has the weakest anisotropy among all the compounds.

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“…This is, however, in contrast with the present study where crystallization of BaSO 4 is noted instead of Na 2 SO 4 . A lower free energy of formation of BaSO 4 as compared with Na 2 SO 4 is perhaps responsible in this case 20 …”

Section: Resultsmentioning

confidence: 84%

Role of Sulfate in Structural Modifications of Sodium Barium Borosilicate Glasses Developed for Nuclear Waste Immobilization

Mishra

Sudarsan

Sengupta

et al. 2008

Journal of the American Ceramic Society

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A sodium barium borosilicate glass matrix with a higher solubility of sulfate has been developed recently at Bhabha Atomic Research Centre for vitrification of sulfate bearing high-level nuclear waste. We report here the studies carried out to understand the influence of sulfate ion on the three-dimensional borosilicate network. Experiments were carried out with sodium barium borosilicate base glass samples loaded with varying amounts of SO 4 2À (0-5 mol%). Phase separation studies on the samples revealed that as much as 3 mol% of SO 4 2À can be loaded within the base glass without any phase separation, however, beyond this limit BaSO 4 (barite) crystallizes within the matrix. Thermal analyses of the samples indicated a shift in glass transition temperature from 5341 (0 mol% SO 4 2À ) to 4951C (3 mol% SO 4 2À ) and it remained more or less unaltered afterwards even with high SO 4 2À loading. A similar observation of structure stabilization was obtained from 29 Si MAS-NMR studies also, which showed that with 2 mol% of SO 4 2À loading, the Q 2 :Q 3 ratio changed from 59:41 (for samples with 0 mol% SO 4 2À loading) to 62:38 and it remained almost the same afterwards even with higher SO 4 2À loading. 11 B MAS NMR patterns of the glass samples, however, remained unchanged with SO 4 2À loading ([BO 4 ]:[BO 3 ] 5 38:62). Based on 29 Si and 11 B MAS NMR studies, the authors propose two different ways of interaction of SO 4 2À ions with the borosilicate network: (i) the network modifying action of SO 4 2À ions with -Si-O-Si-linkages, at low SO 4 2À ion concentration (o2 mol%) and (ii) the preferential interaction of SO 4 2À with the Ba 21 ions at high SO 4 2À concentration (42 mol%).

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Selected values of chemical thermodynamic properties :

Cited by 77 publications

References 0 publications

A first principle study of adsorption of two proximate nitrogen atoms on graphene

A first principle study of adsorption of two proximate nitrogen atoms on graphene

Stability, Mechanical Properties and Anisotropic Elastic Properties of GaxMgy Compounds

Role of Sulfate in Structural Modifications of Sodium Barium Borosilicate Glasses Developed for Nuclear Waste Immobilization

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