Year: 2009
Type: article
Abstract: It has been determined that on depend on various growth conditions in crystals and type of their synthesis the multicomponent layered crystals have a big variety of polytypic and polymorphic modifications.Not only separate crystal's bits taken from various places of the same ampoule may distinguish by their structures but many other polytypic phases can also exist in the same crystal.It is naturally that the presence of one phase on the basis of another one is connecting with packing defects of sulphur atoms and formation of cation's base of a new phase.Deficit of sulphur atoms as a rule is leading to change the cation's valency in crystals as a result of which the ionic radius of cations are also changed and element's base of a new phase is forming.An increase of octahedral (O) position's shares due to decrease of tetrahedral (T) ones in ÒÒÎÒÒE, ÒÎÒÒE, ÒÎÒE, ÒÎÒE2ÒÎÒE1ÎÎE1, ÒÎE, ÒÎÒEÎE, ÒÎÒE1ÎÎE1 types of structural units stimulates creation of such a phases.In these structures the shares of octahedral position in common tetrahedral and octahedral share's positions are as followed: 20%, 25%, 33%, 50%, 50%, 50%, 60%.In case when cations have a permanent valences a creation of a new phase becomes impossible and for packing defects of sulphur atoms only compositional faults are coming up.
Authors: Yves Watier, Irene Margiolaki, Jonathan Wright, Andrew Fitch, Mathias Norrman, Gerd Schluckebier
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W4229938484