Disordering and the progress of hydration at the surface of diopside: A cross-polarization MAS-NMR study

Journal Article · Thu Dec 01 04:00:00 EST 1988 · Geochimica et Cosmochimica Acta; (USA)

DOI:https://doi.org/10.1016/0016-7037(88)90165-2· OSTI ID:5127329

Peck, J A; Farnan, I; Stebbins, J F ^[1]

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1. Stanford Univ., CA (USA)

Samples of synthetic crystalline diopside were prepared with different volumes of surface phase by varying the time of grinding of each sample, and then investigated using {sup 29}Si MAS-NMR. Hydration of the surface, which begins during grinding in laboratory air, allows the surface phase to be detected using {sup 1}H-{sup 29}Si CP MAS-NMR. The surface phase appears to be structurally similar to diopside glass. Several hours of reaction with aqueous solution promotes the formation of Q{sub 2}-(OH){sub 2}, which is indicated by the appearance of a peak in the CP-MAS spectrum at {minus}93 ppm. The progress of hydration appears to be relatively independent of the pH of the aqueous solution.

• OSTI ID: 5127329
• Journal Information: Geochimica et Cosmochimica Acta; (USA), Journal Name: Geochimica et Cosmochimica Acta; (USA) Vol. 52:12; ISSN GCACA; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
CHEMICAL COMPOSITION
CHEMICAL REACTIONS
CHEMICAL SHIFT
CHEMISTRY
COMMINUTION
DIOPSIDE
DISSOLUTION
GEOCHEMISTRY
GRINDING
HYDRATION
MACHINING
MAGNETIC RESONANCE
MINERALS
NUCLEAR MAGNETIC RESONANCE
OXYGEN COMPOUNDS
PH VALUE
PYROXENES
RESONANCE
SILICATE MINERALS
SILICATES
SILICON COMPOUNDS
SOLVATION
SPECTROSCOPY
STRUCTURAL CHEMICAL ANALYSIS
SURFACE PROPERTIES