lnu.sePublications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
X-ray and UV-Vis-NIR absorption spectroscopy studies of the Cu(I) and Cu(II) coordination environments in mixed alkali-lime-silicate glasses
Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. RISE Research Institutes of Sweden, Sweden. (Glass group)
Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. (Glass group)
RISE Research Institutes of Sweden, Sweden;Friedrich Schiller University of Jena, Germany.
Friedrich Schiller University of Jena, Germany.
Show others and affiliations
2019 (English)In: Journal of Non-Crystalline Solids: X, ISSN 2590-1591, article id 100029Article in journal (Refereed) Published
Abstract [en]

The local structures of Cu(I) and Cu(II) in (20-x)Na2O-xK2O-10CaO-70SiO2 glasses with a copper content of 0.4 mol% have been investigated by Cu K-edge extended X-ray absorption fine structure (EXAFS) and X-ray absorption near edge structure (XANES). Complementary data for Cu(II) was derived using UV–Vis-NIR spectroscopy. Indication for mainly linear two-fold coordination of the Cu+ ion was found by both EXAFS and XANES, but other coordination between Cu+ and O2– cannot be excluded. The Cu(I)O bond lengths were found to be 1.79–1.83 ± 0.02 Å. EXAFS results showed that Cu(II) was mostly present in a Jahn-Teller distorted environment with oxygen, an octahedron with four shorter Cu(II)O bonds and two longer in axial position. The equatorial bond lengths were found to be 1.89–1.91 ± 0.02 Å and the axial 2.20–2.24 ± 0.02 Å with no effect of the Jahn-Teller distortion of the octahedron when the glass composition was altered.

Place, publisher, year, edition, pages
Elsevier, 2019. article id 100029
National Category
Ceramics Materials Chemistry
Research subject
Technology (byts ev till Engineering), Glass Technology
Identifiers
URN: urn:nbn:se:lnu:diva-46870DOI: 10.1016/j.nocx.2019.100029Scopus ID: 2-s2.0-85068376725OAI: oai:DiVA.org:lnu-46870DiVA, id: diva2:864128
Available from: 2015-10-26 Created: 2015-10-26 Last updated: 2019-09-02Bibliographically approved
In thesis
1. Redox reactions and structure - properties relations in mixed alkali/alkaline earth glasses: - The role of antimony oxides during the fining process- A structural study of copper(I) and copper(II)
Open this publication in new window or tab >>Redox reactions and structure - properties relations in mixed alkali/alkaline earth glasses: - The role of antimony oxides during the fining process- A structural study of copper(I) and copper(II)
2015 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

It is important to optimize glass compositions for their specific purpose but also for the efficiency of the production process, the manufacturing of glass. This will be beneficial economically and environmentally. Today many processes and glass compositions are already optimized, but due to more strict legislation on toxic elements and substances there must be changes in many glass compositions. One of these elements is antimony; the oxide is used as fining agent to obtain a bubble free glass within a reasonable process time. One aim with this thesis is to obtain a deeper understanding of the fining mechanism in 20R2O-10MO-70SiO2 (R=Na and/or K, M = Ca and/or Ba, Mg, Sr) glasses in order to minimise the amount of Sb2O3. Another intention is to study the structure of 20R2O-10CaO-70SiO2 (R = Na, K) with Cu2+ as probe ion and thus get a deeper knowledge of the surrounding glass matrix.  The optical basicity scale is used to determine the acid/base character of the different glass compositions.

 

Fining efficiency results showed a remarkable increase of the number of remaining bubbles when the glass contains either approximately equal amounts of Na and K or Ca and Ba, Mg or Sr. The much higher number of bubbles in the potassium containing glasses compared to the sodium containing is explained by the increase in viscosity, the increase in optical basicity and thus lower oxygen activity. The differences in the fining efficiency when altering alkaline earth ions cannot be explained by the optical basicity values, it seems to be a more complicated situation.

 

This thesis also reports maximum in Vickers hardness and packing density as well as minimum in glass transition temperature for the mixed alkali glasses. The mixed alkaline earth glasses do not exhibit any clear nonlinear behaviour. Raman spectroscopy measurements showed a variation in the network connectivity which has a clear relation to the optical basicity of the different glass compositions. The combination of UV-Vis-NIR and X-ray absorption spectroscopy measurements showed that the coordination sphere for Cu(II) is a tetragonal distorted octahedron with two elongated Cu-O bonds along the z axis. There were no trends in the degree of tetragonal distortion, thus it was about the same for all the investigated glass compositions. Cu(I) is found to be coordinated by two oxygen ligands in mainly linear coordination sphere, evidenced from X-ray absorption spectroscopy.

Place, publisher, year, edition, pages
Växjö: Linnaeus University Press, 2015. p. 73
Series
Linnaeus University Dissertations ; 231
Keywords
Fining, oxygen activity, redox reactions, mixed alkali effect, mixed alkali silicate glasses, copper, antimony
National Category
Civil Engineering
Research subject
Technology (byts ev till Engineering), Glass Technology
Identifiers
urn:nbn:se:lnu:diva-46782 (URN)978-91-87925-82-5 (ISBN)
Public defence
2015-11-06, Södrasalen, Universitetsplatsen 1, Växjö, 13:00 (English)
Opponent
Supervisors
Available from: 2015-10-20 Created: 2015-10-19 Last updated: 2018-12-12Bibliographically approved

Open Access in DiVA

No full text in DiVA

Other links

Publisher's full textScopus

Authority records BETA

Grund Bäck, LinaAli, SharafatJonson, Bo

Search in DiVA

By author/editor
Grund Bäck, LinaAli, SharafatJonson, Bo
By organisation
Department of Built Environment and Energy Technology
CeramicsMaterials Chemistry

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 234 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf