HR: 1340h
AN: V23A-1249    [Abstracts]
TI: Investigation of Li in Clay Interlayers at Different Temperatures by NMR
AU: * Kim, Y
EM: ygkim@knu.ac.kr
AF: Kyungpook National University, Department of Geology, Daegu, 702-701, Korea, Republic of
AU: Lee, J
EM: z9728346@hanmail.net
AF: Kyungpook National University, Department of Geology, Daegu, 702-701, Korea, Republic of
AB: We used ⁶Li and ⁷Li MAS NMR to investigate the environmental changes of Li in the interlayer of clay minerals at room and high (250^oC) temperatures. We also checked the usefulness ⁶Li NMR in studying Li in interlayer. Hectorite, Wyoming-montmorillonite, beidellite, and lepidollite were used for our study. ⁶Li NMR spectra show narrower peaks than those of ⁷Li NMR, but S/N ratio is low and there are no noticeable chemical shift changes, which makes it difficult to apply ⁶Li NMR to get information on Li environment in clay interlayers. ⁷Li NMR spectra, however, show changes in the peak width and quadrupole pattern, providing information on the Li environment in the interlayer, even though the change in chemical shift is not observed. In montmorillonite, two different environments of Li are observed, one having narrow peak with typical quadrupole pattern, and another having broad peak without that pattern. At high temperature, the broad peak becomes relatively, narrow which was also obserbed in the ⁷Li NMR spectra obtained from beidellite, but not hectorite. This changes are attributed to the coordination changes in the water molecules around Li which is tightly bonded on the basal oxygen of Si tetrahedra as inner-sphere complexes. The narrow peak in montmorillnoite can be assigned to the Li bonded as outer-sphere complexes.
DE: 1042 Mineral and crystal chemistry (3620)
DE: 3620 Mineral and crystal chemistry (1042)
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting