Average single bond strength and optical basicity of Na2O- GeO2 glasses

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creativework.keywordsGermanate anomaly, Optical basicity, Single bond strength, Sodium germanate glasses
creativework.publisherCeramic Society of Japanen
dc.contributor.authorDimitrov V.
dc.contributor.authorKomatsu T.
dc.date.accessioned2024-07-10T14:27:03Z
dc.date.accessioned2024-07-10T14:47:26Z
dc.date.available2024-07-10T14:27:03Z
dc.date.available2024-07-10T14:47:26Z
dc.date.issued2009-01-01
dc.description.abstractOn the basis of the thermodynamical approach proposed by Takahashi and Yoshio the Ge-O single bond strengths BGe-O of GeO6 groups denoted as [GeO6], all bridging GeO4 groups denoted as [GeO 4]BO and GeO4 groups with one non-bridging oxygen denoted as [GeO4]-NBO have been determined for xNa 2O.(1-x)GeO2 (x = 5-30 mol%) glasses as follows: 323 kJ/mol for [GeO6], 341 kJ/mol for all bridging [GeO4]BO and 460 kJ/mol for [GeO4]-NBO groups. Equation for the calculation of average single bond strengths BM-O of sodium germanate glasses has been suggested taking into account the contribution of different structural units namely [GeO6], [GeO4]BO and [GeO 4]-NBO groups. It has been found that the average single bond strength BM-O of sodium germanate glasses decreases up to 267 kJ/mol at 25 mol% Na2O due to the formation of [GeO6] groups and increases up to 282.5 kJ/mol at 30 mol% Na2O due to the formation of [GeO4]-NBO groups. The results support the idea that the formation of [GeO6] groups is probably a main reason for the so-called germanate anomaly. The refractive index based optical basicity Λ(no) is sensitive in relation to the germanate anomaly effect and the group basicity follows the sequence: Λ[GeO4]BO < Λ[GeO6] < Λ[GeO4]-NBO. The observed correlation between Λ(no) and BM-O of sodium germanate glasses has been discussed with the presence of Ge(4)-O- Ge(4), Ge(4)-O-Ge(6) and Ge(4)-O-... Na(6) chemical bonds in the glass structure in which in bracket the coordination number of the cation is given. ©2009 The Ceramic Society of Japan.
dc.identifier.doi10.2109/jcersj2.117.1105
dc.identifier.issn1348-6535
dc.identifier.issn1882-0743
dc.identifier.scopusSCOPUS_ID:70350228551en
dc.identifier.urihttps://rlib.uctm.edu/handle/123456789/175
dc.language.isoen
dc.source.urihttps://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=70350228551&origin=inward
dc.titleAverage single bond strength and optical basicity of Na2O- GeO2 glasses
dc.typeArticle
oaire.citation.issue1370
oaire.citation.volume117
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