Effect of Sb2O4 on structural, physical and optical properties of sodium zinc borate glasses

Ghanem, Ashraf Hussein; Eldeem, Abeer H Serag; Ahmed, Azza El Sayed

doi:10.21608/ejphysics.2021.49672.1059

Cited by 1 publication

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“…Antimony oxides find many uses in industrial processes such as in flame retardants, polymerization catalysts, and as additives in brake linings . The mixed valence Sb 2 O 4 (formally Sb III Sb V O 4 ) oxide is also currently being explored for catalytic – and electrochemical use, , with some recent focus on its effects on optical properties. , The structural and vibrational thermodynamic properties of compounds with trivalent Sb III depend on stereoactive lone electronic pairs. These compounds provide an interesting test bed for density functional theory (DFT) calculations with dispersion corrections as they can sometimes lead to unphysical modes.…”

Section: Introductionmentioning

confidence: 99%

Vibrations and Phase Stability in Mixed Valence Antimony Oxide

Moseley,

Juneja,

Daemen

et al. 2023

Inorg. Chem.

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α-Sb 2 O 4 (cervantite) and β-Sb 2 O 4 (clinocervantite) are mixed valence compounds with equal proportions of Sb III and Sb V as represented in the formula Sb III Sb V O 4 . Their structure and properties can be difficult to calculate owing to the Sb III lone-pair electrons. Here, we present a study of the lattice dynamics and vibrational properties using a combination of inelastic neutron scattering, Mossbauer spectroscopy, nuclear inelastic scattering, and density functional theory (DFT) calculations. DFT calculations that account for lone-pair electrons match the experimental densities of phonon states. Mossbauer spectroscopy reveals the β phase to be significantly harder than the α phase. Calculations with O vacancies reveal the possibility for nonstoichiometric proportions of Sb III and Sb V in both phases. An open question is what drives the stability of the α phase over the β phase, as the latter shows pronounced kinetic stability and lower symmetry despite being in the hightemperature phase. Since the vibrational entropy difference is small, it is unlikely to stabilize the α phase. Our results suggest that the α phase is more stable only because the material is not fully stoichiometric.

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