Group-theoretical and geometrical considerations of the phase transition between the high-temperature polymorphs of quartz and tridymite.
A model was derived for the temperature-dependent phase transition between the high-temperature polymorphs of quartz (P6(4)22) and tridymite (P6(3)/mmc). Only the Si framework is considered, and the transformation can be described as a deformation of a homogeneous sphere packing with three contacts per sphere (type 3/10/h1) in the common subgroup P6(1)22 of P6(4)22 and P6(3)/mmc. The proposed model guarantees the three-dimensional connection of the crystal structure during the whole transformation process.
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Institut für Angewandte Geowissenschaften, Allgemeine und Angewandte Mineralogie, Technische Universität BH1, Ernst-Reuter-Platz 1, D-10587 Berlin, Germany.
Koch
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