Effect of the interaction between basicity and reductive character of melting atmosphere – both extreme – on the oxidation and coordination states assumed by transition metals when doped to silicate glasses

Year: 2024

Authors: Zandona A., Castaing V., Shames AI., Helsch G., Pirri A., Toci G., Deubener J., Allix M., Goldstein A.

Autors Affiliation: Univ Orleans, CNRS, CEMHTI UPR3079, F-45071 Orleans, France; Tech Univ Clausthal, Inst Nonmet Mat, D-38678 Clausthal Zellerfeld, Germany; Univ Seville, Inst Ciencia Mat Sevilla ICMS, CSIC, C Americo Vespucio 49, Seville 41092, Spain; Ben Gurion Univ Negev, Dept Phys, IL-8410501 Beer Sheva, Israel; CNR, CNR IFAC, Ist Fis Applicata Carrara, Via Madonna Piano 10C, I-50019 Sesto Fiorentino, Fi, Italy; CNR, CNR INO, Ist Nazl Ott, Via Madonna Piano 10C, I-50019 Florence, Italy; Technion City, Israel Ceram & Silicate Inst, Haifa, Israel.

Abstract: The influence of an extremely reductive melting atmosphere on the oxidation and coordination states adopted by transition metals in an ultrabasic host was evaluated. An invert glass (46SiO(2)center dot 11Na(2)O center dot 21CaO center dot 22BaO, basicity = 0.71) was synthesized in container-less conditions, on a jet of Ar 5%H-2. Performed measurements included optical absorption, optical emission and electron paramagnetic resonance spectroscopy. The results revealed that the used atmosphere dramatically decreases the oxidation state(s) dopants assume, compared to those stable under oxidative melting in such a host. After reductive melting: (i) Ti3+ appears alongside Ti4+; (ii) V3+ is added to V5+; (iii) Mn2+ fully substitutes Mn3+ and Mn5+; (iv) Cu2+ is entirely replaced by Cu(+)and Cu-0. These results could be rationalized considering the action of additional factors like ligand-field stabilization energy, ionization energy and special filling numbers of the 3d-subshell. They modulate the interaction between basicity and atmosphere redox character, in a way specific to each transition metal.

Journal/Review: JOURNAL OF NON-CRYSTALLINE SOLIDS

Volume: 637      Pages from: 123038-1  to: 123038-13

More Information: Alessio Zandona wishes to acknowledge the Deutsche Forschungsgemeinschaft (DFG) for funding his research through the Walter Benjamin Program, project n. 448961237, ZA 1188/1-1 and ZA 1188/2-1. Victor Castaing acknowledges Junta de Andalucia for financial support (POSTDOC_21_00694). Th is project has benefited from the expertise and the facilities of the Platform MACLE-CVL which was co-funded by the European Union and Centre-Val de Loire Region (FEDER) .
KeyWords: Optical basicity; Transition metal doping; Spectroscopy; Oxidative vs. reductive melting atmosphere; Invert glass
DOI: 10.1016/j.jnoncrysol.2024.123038


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