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From: MOORE1
To: RCME
Subject: epitaxial, topotaxial
Date: Thursday, March 09, 1995 1:00PM
To: "Rietveld Method Users" <rietveld@xtal.cmc.uab.edu>
Subject: epitaxial, topotaxial
Hello all,
I need a bit of help. People writing in the discipline of clay
mineralogy and other related disciplines (e.g., surface studies, soils,
general mineralogy), seem to use the terms epitaxial and topotaxial
interchangeably. My general notion is that an epitaxial overgrowth has two
xllographic dimensions in common with its host, whereas topotaxial has
three. What I need is a proclamation by some appropriate nomenclature
committee. Can anyone refer me to a source for definitions of these terms?
We would like to use them in the 2nd edition of Moore and Reynolds, X-Ray
Diff. and the Ident. and Analysis of Clay Minerals.
Thanks for whatever you can do.
**************************************************
Dewey Moore
Illinois State Geological Survey
615 E. Peabody Dr.
Champaign, IL 61820
ph: (217) 244-2529; FAX: (217) 333-2830
A short, official definition of topotaxy can be found in the minutes of the
IMA-IUCr Joint Committee on Nomenclature in Acta Cryst. A33, 681-4(1977).
A more detailed definition with many examples can be found in "Topotactic
Reactions in Inorganic Oxy-Compounds" by L. S> D. Glasser, F. P. Glasser, &
H. F. W. Taylor in Quarterly Reviews 16, 343-60(1962).
Ron Medrud trcme@rrc.chevron.com
Chevron Research & Technology Co.
Richmond, CA