Using High Pressure to Prepare Polymorphs of the Ba2Co1-xZnxS3 (0 <= x <= 1.0) Compounds

In this work, high pressure was used as a tool to
induce structural transition and prepare metastable polymorphs
of ternary sulfides. Structural transformations under
high pressure of compounds belonging to the Ba2Co1-xZnxS3
(0 <= x <= 1.0) series were studied using X-ray diffraction and
electron microscopy. All members of the Ba2Co1-xZnxS3 series
show the Ba2CoS3-type one-dimensional structure, but, after
heating under pressure, the Ba2CoS3 compound (x = 0)
separates into BaS and the two-dimensional BaCoS2-? (? ? 0),
while Ba2Co1-xZnxS3 compounds with x >= 0.25 maintain their one-dimensional features but rearrange into polymorphs showing
the Ba2MnS3-type structure. All structural transformations can be linked to shortening in interchain metal-metal distances
caused by the high pressure, and the role of the zinc in preventing loss of one-dimensionality is discussed.