Metallike behavior of lithium intercalated in molybdenum cluster chalcogenides
| Autor: | R. Schoellhorn, E. Gocke, C. Prigge, W. Mueller-Warmuth |
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| Rok vydání: | 1993 |
| Předmět: | |
| Zdroj: | Chemistry of Materials. 5:1493-1498 |
| ISSN: | 1520-5002 0897-4756 |
| DOI: | 10.1021/cm00034a020 |
| Popis: | Binary and ternary molybdenum cluster chalcogenides are of interest as superconductors. [sup 7]Li solid-state NMR studies have been carried out on the molybdenum cluster chalcogenides ( Chevrel phases') Li[sub 3]Mo[sub 6]X[sub 8], Li[sub 3.8]Mo[sub 6]X[sub 8], and Li[sub 4]Mo[sub 6]X[sub 8] at 16 and 117 MHz and various temperatures. The low-temperature spectra of Li[sub 3]Mo[sub 6]X[sub 8], Li[sub 3.8]Mo[sub 6]X[sub 8], and Li[sub 4]Mo[sub 6]x[sub 8] can be interpreted in terms of chemical shift (CS), nuclear quadrupole (Q), and dipole-diple (D) interaction, where the principal axes of the CS and Q tensors do not coincide. The spin-lattice relaxation of these compounds is governed by contributions from the lithium diffusion and from the interaction with conduction electrons. The latter part is connected with the isotropic (Knight) shift by a Korrienga relation. The formation of lithium triclusters with partial charge transfer to the host lattice, short Li-Li distances and remaining electron density in the 2s orbitals is concluded from the various data. In Li[sub 4]Mo[sub 6]X[sub 8] by contrast, the intercalated lithium is completely ionized. Models for structure and motion have been developed in connection with recent neutron diffraction studies. 12 refs., 8 figs., 2 tabs. |
| Databáze: | OpenAIRE |
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