Details
| Original language | English |
|---|---|
| Pages (from-to) | 65-74 |
| Number of pages | 10 |
| Journal | Solid state sciences |
| Volume | 60 |
| Early online date | 5 Aug 2016 |
| Publication status | Published - Oct 2016 |
Abstract
The capability of mechanochemical synthesis for the formation of solid solutions of alkaline earth metal fluorides Ma1−xMbxF2 (M: Ca, Sr, Ba) was tested by fluorination of metal acetates and metal hydroxides with ammonium fluoride directly at milling. Evidence was found for a mutual substitution of cations on their lattice positions in Ca1−xSrxF2 and Ba1−xSrxF2 samples. For the Ba/Ca-system this synthesis route is only partially successful. X-ray diffraction and 19F MAS NMR spectroscopy were used to characterize all samples concerning their crystal structure and local fluorine coordination. Calculations of 19F chemical shifts with the superposition model along with probability calculations for the intensity of the individual 19F lines, performed in dependence on the molar composition of the samples, perfectly agree with the experimental findings. The fluoride ion conductivity of as-prepared samples, determined by temperature dependent DC conductivity measurements, is significantly higher than those of crystalline binary fluorides. Moreover, a higher F− ion conductivity is observed for samples with higher mixing grade in the Ca/Sr-and the Ba/Sr-systems.
Keywords
- F MAS NMR spectroscopy, Mechanochemical synthesis, Solid solutions MM′F
ASJC Scopus subject areas
- Chemistry(all)
- General Chemistry
- Materials Science(all)
- General Materials Science
- Physics and Astronomy(all)
- Condensed Matter Physics
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In: Solid state sciences, Vol. 60, 10.2016, p. 65-74.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Mechanochemical synthesis, structure, and properties of solid solutions of alkaline earth metal fluorides:
T2 - Ma1−xMbxF2 (M: Ca, Sr, Ba)
AU - Heise, M.
AU - Scholz, G.
AU - Düvel, A.
AU - Heitjans, P.
AU - Kemnitz, E.
N1 - Funding Information: The authors of the Humboldt-Universität zu Berlin want to thank the research training network GRK 1582/2 “Fluorine as a Key Element” of DFG ( Deutsche Forschungsgemeinschaft ) for funding. A. D. wants to thank the Leibniz Universität Hannover for research funding within the frame of “Wege in die Forschung II”. Dr. Thoralf Krahl is kindly acknowledged for discussions, the PhD student Dorota Bartkowiak for TEM measurements and Melchior Schröter for few milling experiments.
PY - 2016/10
Y1 - 2016/10
N2 - The capability of mechanochemical synthesis for the formation of solid solutions of alkaline earth metal fluorides Ma1−xMbxF2 (M: Ca, Sr, Ba) was tested by fluorination of metal acetates and metal hydroxides with ammonium fluoride directly at milling. Evidence was found for a mutual substitution of cations on their lattice positions in Ca1−xSrxF2 and Ba1−xSrxF2 samples. For the Ba/Ca-system this synthesis route is only partially successful. X-ray diffraction and 19F MAS NMR spectroscopy were used to characterize all samples concerning their crystal structure and local fluorine coordination. Calculations of 19F chemical shifts with the superposition model along with probability calculations for the intensity of the individual 19F lines, performed in dependence on the molar composition of the samples, perfectly agree with the experimental findings. The fluoride ion conductivity of as-prepared samples, determined by temperature dependent DC conductivity measurements, is significantly higher than those of crystalline binary fluorides. Moreover, a higher F− ion conductivity is observed for samples with higher mixing grade in the Ca/Sr-and the Ba/Sr-systems.
AB - The capability of mechanochemical synthesis for the formation of solid solutions of alkaline earth metal fluorides Ma1−xMbxF2 (M: Ca, Sr, Ba) was tested by fluorination of metal acetates and metal hydroxides with ammonium fluoride directly at milling. Evidence was found for a mutual substitution of cations on their lattice positions in Ca1−xSrxF2 and Ba1−xSrxF2 samples. For the Ba/Ca-system this synthesis route is only partially successful. X-ray diffraction and 19F MAS NMR spectroscopy were used to characterize all samples concerning their crystal structure and local fluorine coordination. Calculations of 19F chemical shifts with the superposition model along with probability calculations for the intensity of the individual 19F lines, performed in dependence on the molar composition of the samples, perfectly agree with the experimental findings. The fluoride ion conductivity of as-prepared samples, determined by temperature dependent DC conductivity measurements, is significantly higher than those of crystalline binary fluorides. Moreover, a higher F− ion conductivity is observed for samples with higher mixing grade in the Ca/Sr-and the Ba/Sr-systems.
KW - F MAS NMR spectroscopy
KW - Mechanochemical synthesis
KW - Solid solutions MM′F
UR - http://www.scopus.com/inward/record.url?scp=84982273144&partnerID=8YFLogxK
U2 - 10.1016/j.solidstatesciences.2016.08.004
DO - 10.1016/j.solidstatesciences.2016.08.004
M3 - Article
AN - SCOPUS:84982273144
VL - 60
SP - 65
EP - 74
JO - Solid state sciences
JF - Solid state sciences
SN - 1293-2558
ER -