1051. Europium- and ytterbium-ammonia graphite intercalation compounds
- Author
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H.-J. Hummel, M. Höhne, Yichen Wang, and E. Stumpp
- Subjects
Ytterbium ,Thermogravimetric analysis ,Chemistry ,Inorganic chemistry ,Intercalation (chemistry) ,chemistry.chemical_element ,General Chemistry ,law.invention ,Metal ,law ,visual_art ,X-ray crystallography ,visual_art.visual_art_medium ,General Materials Science ,Graphite ,Europium ,Electron paramagnetic resonance - Abstract
Europium- and ytterbium-ammonia graphite intercalation compounds (REMA-GICs) were synthesized by the reaction of Eu-NH 3 and Yb-NH 3 solutions and characterized by powder x-ray diffraction, thermogravimetric analysis, as well as electron paramagnetic resonance (EPR) spectra. An improved preparation technique is presented. Concentrated, bronze-coloured REMA solutions react to give REMA-GICs with a high metal content and the approximate formula M ( NH 3 ) x C 8 ( M = Eu , Yb ). They consist of cointercalated metal ammine and excess metal. If graphite is treated with dilute blue REMA solutions, pure stage 1, 2, and 3 REMA-GICs can be prepared. The d i values of stage 1 Eu-NH 3 and Yb-NH 3 GICs obtained from dilute or concentrated REMA solutions are identical and were found to be 624 pm and 644 pm, respectively. The absence of EPR signals for the REMA-GICs at room temperature is discussed.
- Published
- 1991
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