ISSN:
1573-1421
Schlagwort(e):
dolomite crystal structure
;
dolomite x-ray diffraction
;
dolomite electron microscopy
;
dolomite
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Chemie und Pharmazie
,
Geologie und Paläontologie
Notizen:
Abstract Most sedimentary Ca-rich dolomite in pre-Holocenerocks is known to exhibit a fine-scale modulation inTEM images, reflecting a domain structure of which onecomponent is a low-symmetry variant of dolomite. Thevarious structural models proposed for thelow-symmetry component involve Ca–Mg order patternsthat are different from that in dolomite. Caution istherefore required for interpretation of X-raydiffraction data, which average over the entirestructure. The average structures of two Ca-richdolomites having a structural modulation are refinedusing single-crystal intensity data. The resultsindicate a poor fit using a dolomite model, which isconsistent with the findings from TEM and electrondiffraction indicating that one component of thedomain structure is different than dolomite. Resultsalso indicate that average model A and B cation siteshave mixed Ca–Mg occupancy, which provides someconstraints on possible models for the low-symmetrydomains.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1023/A:1009659122772
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