High Pressure Polymerization of the Li-Intercalated Fulleride Li3CsC60
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- 作者：Serena Margadonna ; Kosmas Prassides ; Kenneth D. Knudsen ; Michael Hanfland ; Mayumi Kosaka ; and Katsumi Tanigaki
- 刊名：Chemistry of Materials
- 出版年：1999
- 出版时间：October 1999
- 年：1999
- 卷：11
- 期：10
- 页码：2960 - 2965
- 全文大小：131K
- 年卷期：v.11,no.10(October 1999)
- ISSN：1520-5002
文摘
The structural features of the superconducting Li3CsC60 fulleride are studied by synchrotron X-ray powder diffraction as a function of pressure and temperature. In contrast withthe behavior of Li2CsC60, Li3CsC60 shows a phase transition below room temperature fromfcc (space group Fm
m) to an orientationally ordered primitive cubic phase (space groupPa), isostructural with the metastable phases of Na2A'C60. Despite the slow cooling protocolsadopted, the system shows no other phase transitions even after prolonged standing at 200K. The pressure dependence of the structure of Li3CsC60 at ambient temperature was followedup to 8.12 GPa. A phase transition occurs at 0.72 GPa to a low symmetry fullerene bridgedpolymeric phase with short center-to-center interfullerene separations of ~9.38 Å. This phasewas found to be monoclinic (space group P21/a), isostructural with the low-temperaturepolymer phase of Na2RbC60 and the high-pressure polymer phase of Na2CsC60. The pressureevolution of the monoclinic lattice constants reveals a highly incompressible, tightly packed,and strongly anisotropic polymeric structure.
m) to an orientationally ordered primitive cubic phase (space groupPa), isostructural with the metastable phases of Na2A'C60. Despite the slow cooling protocolsadopted, the system shows no other phase transitions even after prolonged standing at 200K. The pressure dependence of the structure of Li3CsC60 at ambient temperature was followedup to 8.12 GPa. A phase transition occurs at 0.72 GPa to a low symmetry fullerene bridgedpolymeric phase with short center-to-center interfullerene separations of ~9.38 Å. This phasewas found to be monoclinic (space group P21/a), isostructural with the low-temperaturepolymer phase of Na2RbC60 and the high-pressure polymer phase of Na2CsC60. The pressureevolution of the monoclinic lattice constants reveals a highly incompressible, tightly packed,and strongly anisotropic polymeric structure.