In:
Clays and Clay Minerals, Cambridge University Press (CUP), Vol. 55, No. 2 ( 2007-04), p. 220-232
Abstract:
An ab initio theoretical approach has been used to calculate optimized geometries and the relative energies of various compositional arrangements in structures of dioctahedral smectites based on models consisting of two unit-cells. These calculations indicate that the energy differences between structures having vacancies in sites with cis - or trans -OH coordination are small and that their relative energies vary with the chemical nature of the substitutions. For example, a cis -OH coordination for the vacancy was the most stable when the interlayer charge originated from substitution of Al for Si in the tetrahedral sheet, whereas the trans -coordination was the more stable for most cases of substitution in the octahedral sheet, an exception being Fe(II) for Al where the cis -OH coordination was favored. It seems likely, therefore, that long-range structural disorder will be a common phenomenon in natural phyllosilicate specimens.
Type of Medium:
Online Resource
ISSN:
0009-8604
,
1552-8367
DOI:
10.1346/CCMN.2007.0550211
Language:
English
Publisher:
Cambridge University Press (CUP)
Publication Date:
2007
detail.hit.zdb_id:
2045991-9
detail.hit.zdb_id:
221428-3
SSG:
13
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