TY - JOUR
T1 - Partitioning and structural role of Mn and Fe ions in ionic sulfophosphate glasses
AU - Möncke, Doris
AU - Sirotkin, Sergey
AU - Stavrou, Elissaios
AU - Kamitsos, Efstratios I.
AU - Wondraczek, Lothar
N1 - Publisher Copyright:
© 2014 AIP Publishing LLC.
PY - 2014/12/14
Y1 - 2014/12/14
N2 - Ionic sulfophosphate liquids of the type ZnO-Na2O-Na2SO4-P2O5 exhibit surprising glass forming ability, even at slow or moderate cooling rate. As a concept, they also provide high solubility of transition metal ions which could act as cross-linking sites between the sulfate and phosphate entities. It is therefore investigated how the replacement of ZnO by MnO and/or FeO affects the glass structure and the glass properties. Increasing manganese levels are found to result in a monotonic increase of the transition temperature Tg and most of the mechanical properties. This trend is attributed to the change of metal-ion coordination from four-fold around Zn2+ to six-fold around Mn2+ ions. The higher coordination facilitates cross-linking of the ionic structural entities and subsequently increases Tg. Raman and infrared spectroscopy show that the structure of these glasses involves only SO42- and PO43- monomers as well as P2O74- dimers. Replacement of ZnO by MnO is found to favour PO43- over P2O74- species, a trend which is enhanced by co-doping with FeO. Both transition metal ions show, like Zn2+, a preference to selectively coordinate to phosphate anionic species, as opposed to sodium ions which coordinate mainly to sulfate anions. EPR spectroscopy finally shows that divalent Mn2+ ions are present primarily in MnO6-clusters, which, in the studied sulfophosphate glasses, convert upon increasing MnO content from corner-sharing to edge-sharing entities.
AB - Ionic sulfophosphate liquids of the type ZnO-Na2O-Na2SO4-P2O5 exhibit surprising glass forming ability, even at slow or moderate cooling rate. As a concept, they also provide high solubility of transition metal ions which could act as cross-linking sites between the sulfate and phosphate entities. It is therefore investigated how the replacement of ZnO by MnO and/or FeO affects the glass structure and the glass properties. Increasing manganese levels are found to result in a monotonic increase of the transition temperature Tg and most of the mechanical properties. This trend is attributed to the change of metal-ion coordination from four-fold around Zn2+ to six-fold around Mn2+ ions. The higher coordination facilitates cross-linking of the ionic structural entities and subsequently increases Tg. Raman and infrared spectroscopy show that the structure of these glasses involves only SO42- and PO43- monomers as well as P2O74- dimers. Replacement of ZnO by MnO is found to favour PO43- over P2O74- species, a trend which is enhanced by co-doping with FeO. Both transition metal ions show, like Zn2+, a preference to selectively coordinate to phosphate anionic species, as opposed to sodium ions which coordinate mainly to sulfate anions. EPR spectroscopy finally shows that divalent Mn2+ ions are present primarily in MnO6-clusters, which, in the studied sulfophosphate glasses, convert upon increasing MnO content from corner-sharing to edge-sharing entities.
UR - http://www.scopus.com/inward/record.url?scp=84916228294&partnerID=8YFLogxK
U2 - 10.1063/1.4903191
DO - 10.1063/1.4903191
M3 - 文章
AN - SCOPUS:84916228294
SN - 0021-9606
VL - 141
JO - Journal of Chemical Physics
JF - Journal of Chemical Physics
IS - 22
M1 - 224509
ER -