ISSN:
1600-5740
Source:
Crystallography Journals Online : IUCR Backfile Archive 1948-2001
Topics:
Chemistry and Pharmacology
,
Geosciences
,
Physics
Notes:
The structural behavior of the antifluorite Na2S, disodium sulfide, has been studied under pressure up to 22 GPa by in situ synchrotron X-ray diffraction experiments in a diamond anvil cell at room temperature. At approximately 7 GPa, Na2S undergoes a first phase transition to the orthorhombic anticotunnite (PbCl2) structure (Pnma, Z = 4). The lattice parameters at 8.2 GPa are a = 6.707 (5), b = 4.120 (3), c = 8.025 (4) Å. At approximately 16 GPa, Na2S undergoes a second transition adopting the structure of the Ni2In-type (P63/mmc, Z = 2). The lattice parameters at 16.6 GPa are a = 4.376 (18), c = 5.856 (9) Å. Both pressure-induced phases have been confirmed by full Rietveld refinements. An inspection of the cation array of Na2SO4 reveals that its Na2S subarray is also of the Ni2In-type. This feature represents a new example of how the cation arrangements in ternary oxides correspond to the topology of the respective binary compounds. We discuss analogies between the insertion of oxygen and the application of pressure.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1107/S0108768100016621
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