/sup 6/Li as a probe for the study of the NMR (nuclear magnetic resonance) of lithium ions in dehydrated and partially dehydrated zeolite A
The /sub 6/Li isotope has been used in a multinuclear magnetic resonance (NMR) study of A-type zeolite ion-exchanged with lithium. NMR spectra and spin-lattice relaxation times have been measured for /sup 6/Li, /sup 7/Li, /sup 23/Na, /sup 27/Al, and /sup 29/Si in dehydrated and partially dehydrated samples of the zeolite. By use of a sample containing eight /sup 6/Li/sup +/ ions in the unit cell, it is shown that the Li/sup +/ ions preferentially (and exclusively) occupy the eight six-ring sites in the fully dehydrated A zeolite, but that this preference is reversed as long as the zeolite is not completely dehydrated. Li/sup +/ ions are found in both the eight-ring and six-ring sites in the presence of very small amounts of residual water. Evidence in the literature indicates that Li/sup +/ ions occupy only the six-ring sites in A-type zeolite which is partially rehydrated after being fully dehydrated. The distinction between the /sup 6/Li/sup +/ ions in the two types of sites was made on the basis of differences in their quadrupole coupling constants and relaxation times. In the fully dehydrated zeolite, the Li/sup +/ ion in the six-ring site has a quadrupole coupling constant of 3.83 kHz in an electric field gradient of approximately axial symmetry. Determination of its magnitude is facilitated by the small quadrupole moment of the /sup 6/Li isotope. 19 refs., 2 figs., 3 tabs.
- Research Organization:
- Argonne National Lab., IL (USA)
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 6358567
- Report Number(s):
- ANL/PPRNT-89-178; ON: DE89008472
- Country of Publication:
- United States
- Language:
- English
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75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALI METAL COMPOUNDS
ALKALI METAL ISOTOPES
ALUMINIUM 27
ALUMINIUM ISOTOPES
CHARGED PARTICLES
CHLORIDES
CHLORINE COMPOUNDS
COUPLING CONSTANTS
EVEN-ODD NUCLEI
HALIDES
HALOGEN COMPOUNDS
HYDRATION
INORGANIC ION EXCHANGERS
ION EXCHANGE
ION EXCHANGE MATERIALS
IONS
ISOTOPES
LIGHT NUCLEI
LITHIUM 6
LITHIUM 7
LITHIUM CHLORIDES
LITHIUM COMPOUNDS
LITHIUM HALIDES
LITHIUM IONS
LITHIUM ISOTOPES
MATERIALS
MINERALS
MOLECULAR STRUCTURE
NMR SPECTRA
NUCLEI
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
RELAXATION
SILICON 29
SILICON ISOTOPES
SODIUM COMPOUNDS
SOLVATION
SPECTRA
SPIN-LATTICE RELAXATION
STABLE ISOTOPES
ZEOLITES