X-ray and UV–Vis-NIR absorption spectroscopy studies of the Cu (I) and Cu (II) coordination environments in mixed alkali-lime-silicate glasses

• 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.

Ämnesord

NATURVETENSKAP  -- Kemi -- Materialkemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Materials Chemistry (hsv//eng)

NATURVETENSKAP  -- Kemi -- Oorganisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Inorganic Chemistry (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Keramteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Ceramics (hsv//eng)

Nyckelord

Mixed alkali

Ligand Field Theory

UV-Vis-NIR

EXAFS

XANES

Jahn-Teller distortion

Silicate glass

Glasteknologi

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