Novel high pressure monoclinic Fe2O3 polymorph revealed by single-crystal synchrotron X-ray diffraction studies

Title data

Bykova, Elena ; Bykov, Maxim ; Prakapenka, Vitali B. ; Konôpková, Zuzana ; Liermann, Hanns-Peter ; Dubrovinskaia, Natalia ; Dubrovinsky, Leonid:
Novel high pressure monoclinic Fe2O3 polymorph revealed by single-crystal synchrotron X-ray diffraction studies.
In: High Pressure Research. Vol. 33 (2013) Issue 3 . - pp. 534-545.
ISSN 1477-2299
DOI: https://doi.org/10.1080/08957959.2013.833613

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Abstract in another language

A novel high pressure polymorph of iron sesquioxide, m-Fe2O3, has been identified by means of single-crystal synchrotron X-ray diffraction (XRD). Upon compression of a single crystal of hematite, α-Fe2O3, in a diamond anvil cell, the transition occurs at pressure of about 54 GPa and results in ∼10% volume reduction. The crystal structure of the new phase was solved by the direct method (monoclinic space group P21/n, a=4.588(3), b=4.945(2), c=6.679(7) Å and β=91.31(9)°) and refined to R1 ∼11%. It belongs to the cryolite double-perovskite structure type and consists of corner-linked FeO6 octahedra and FeO6 trigonal prisms filling the free space between the octahedra. Upon compression up to ∼71 GPa at ambient temperature no further phase transitions were observed. Laser heating to ∼ 2100±100 K promotes a transition to the Cmcm CaIrO3-type (post-perovskite (PPv)) phase. The PPv-Fe2O3 crystal structure was refined by means of single-crystal XRD at ∼65 GPa. On decompression the PPv-Fe2O3 phase fully transforms back to hematite at pressures between ∼25 and 15 GPa.

Further data

Item Type:	Article in a journal
Refereed:	Yes
Institutions of the University:	Faculties > Faculty of Mathematics, Physics und Computer Science > Group Material Sciences > Chair Crystallography Faculties > Faculty of Mathematics, Physics und Computer Science > Group Material Sciences > Professor Materials Physics and Technology at Extreme Conditions > Professor Materials Physics and Technology at Extreme Conditions - Univ.-Prof. Dr. Natalia Doubrovinckaia Faculties Faculties > Faculty of Mathematics, Physics und Computer Science Faculties > Faculty of Mathematics, Physics und Computer Science > Group Material Sciences Faculties > Faculty of Mathematics, Physics und Computer Science > Group Material Sciences > Professor Materials Physics and Technology at Extreme Conditions
Result of work at the UBT:	Yes
DDC Subjects:	500 Science > 530 Physics
Date Deposited:	27 Jul 2015 08:43
Last Modified:	01 Jun 2022 11:27
URI:	https://eref.uni-bayreuth.de/id/eprint/17184