Revisiting kaolinite dehydroxylation: A sup 29 Si and sup 27 Al MAS NMR study

Journal Article · Wed May 10 00:00:00 EDT 1989 · Journal of the American Chemical Society; (USA)

DOI:https://doi.org/10.1021/ja00192a005· OSTI ID:6884846

Lambert, J F; Millman, W S; Fripiat, J J ^[1]

---

1. Univ. of Wisconsin, Madison (USA)

The {sup 29}Si and {sup 27}Al MAS NMR spectra of kaolinite are easily interpreted in terms of a Q{sup 3} environment for silicon and of an octahedral configuration of aluminum. Upon progressive dehydroxylation, these spectra become more complex. For a degree of dehydroxylation ({alpha}) between 1/10 and 9/10, three {sup 27}Al resonances are observed at +3, +28, and +55 ppm. The octahedral component decreases in intensity as {alpha} increases, whereas the other two become dominant. The line at +28 ppm is assigned to pentacoordinated Al, as suggested by Gilson et al. The +55-ppm line is attributed to tetrahedrally coordinated Al. Simultaneously, the {minus}91-ppm (initial) component of the {sup 29}Si spectrum decreases in intensity, while at least two components corresponding to more shielded Si nuclei grow in intensity. As {alpha} increases beyond 9/10, further shifts are observed in the {sup 29}Si spectra as mentioned by Meinhold et al. Ultimately a line at {minus}109 ppm suggests a significant proportion of the {sup 29}Si nuclei being in a Q{sup 4} environment, while the {sup 27}Al spectrum is reminiscent of that of a spinel-like material. The relationships between the {sup 29}Si and {sup 27}Al spectra are discussed and compared with IR data in the 1,200-400-cm{sup {minus}1} range and with earlier results on {sup 1}H (static) NMR.

• OSTI ID: 6884846
• Journal Information: Journal of the American Chemical Society; (USA), Journal Name: Journal of the American Chemical Society; (USA) Vol. 111:10; ISSN 0002-7863; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360000* -- Materials
360602 -- Other Materials-- Structure & Phase Studies
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400101 -- Activation
Nuclear Reaction
Radiometric & Radiochemical Procedures
ALUMINIUM 27
ALUMINIUM COMPOUNDS
ALUMINIUM ISOTOPES
ALUMINIUM SILICATES
DATA
DATA ANALYSIS
EVEN-ODD NUCLEI
EXPERIMENTAL DATA
INFORMATION
ISOTOPES
KAOLINITE
LIGHT NUCLEI
MAGNETIC RESONANCE
MEASURING INSTRUMENTS
MEASURING METHODS
MINERALS
NUCLEAR MAGNETIC RESONANCE
NUCLEI
NUMERICAL DATA
ODD-EVEN NUCLEI
OXYGEN COMPOUNDS
RESONANCE
SILICATE MINERALS
SILICATES
SILICON 29
SILICON COMPOUNDS
SILICON ISOTOPES
STABLE ISOTOPES