Crystallography relevant to Mars and Galilean icy moons: crystal behavior of kieserite-type monohydrate sulfates at extraterrestrial conditions down to 15 K.

Autor: Wildner M; Department of Mineralogy and Crystallography, University of Vienna, Althanstraße 14, A-1090 Wien, Austria., Zakharov BA; Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences, Lavrentieva Avenue 5, Novosibirsk 630090, Russian Federation.; Novosibirsk State University, Pirogova Street 2, Novosibirsk 630090, Russian Federation., Bogdanov NE; Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences, Lavrentieva Avenue 5, Novosibirsk 630090, Russian Federation.; Novosibirsk State University, Pirogova Street 2, Novosibirsk 630090, Russian Federation., Talla D; Department of Mineralogy and Crystallography, University of Vienna, Althanstraße 14, A-1090 Wien, Austria., Boldyreva EV; Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences, Lavrentieva Avenue 5, Novosibirsk 630090, Russian Federation.; Novosibirsk State University, Pirogova Street 2, Novosibirsk 630090, Russian Federation., Miletich R; Department of Mineralogy and Crystallography, University of Vienna, Althanstraße 14, A-1090 Wien, Austria.
Jazyk: angličtina
Zdroj: IUCrJ [IUCrJ] 2022 Jan 11; Vol. 9 (Pt 2), pp. 194-203. Date of Electronic Publication: 2022 Jan 11 (Print Publication: 2022).
DOI: 10.1107/S2052252521012720
Abstrakt: Monohydrate sulfate kieserites ( M 2+ SO 4 ·H 2 O) and their solid solutions are essential constituents on the surface of Mars and most likely also on Galilean icy moons in our solar system. Phase stabilities of end-member representatives ( M 2+ = Mg, Fe, Co, Ni) have been examined crystallographically using single-crystal X-ray diffraction at 1 bar and temperatures down to 15 K, by means of applying open He cryojet techniques at in-house laboratory instrumentation. All four representative phases show a comparable, highly anisotropic thermal expansion behavior with a remarkable negative thermal expansion along the monoclinic b axis and a pronounced anisotropic expansion perpendicular to it. The lattice changes down to 15 K correspond to an 'inverse thermal pressure' of approximately 0.7 GPa, which is far below the critical pressures of transition under hydro-static compression ( P c ≥ 2.40 GPa). Consequently, no equivalent structural phase transition was observed for any compound, and neither dehydration nor rearrangements of the hydrogen bonding schemes have been observed. The M 2+ SO 4 ·H 2 O ( M 2+ = Mg, Fe, Co, Ni) end-member phases preserve the kieserite-type C 2/ c symmetry; hydrogen bonds and other structural details were found to vary smoothly down to the lowest experimental temperature. These findings serve as an important basis for the assignment of sulfate-related signals in remote-sensing data obtained from orbiters at celestial bodies, as well as for thermodynamic considerations and modeling of properties of kieserite-type sulfate monohydrates relevant to extraterrestrial sulfate associations at very low temperatures.
(© Manfred Wildner et al. 2022.)
Databáze: MEDLINE
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