Crystal structure of the thortveitite-related M phase, (Mn<sub>x</sub>Zn<sub>1-x</sub>)<sub>2</sub>V<sub>2</sub>O<sub>7</sub> (0.75 < x < 0.913): a combined synchrotron powder and single-crystal X-ray study.
Acta crystallographica. Section C, Structural chemistry
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Knowles, K., Sil, A., Stöger, B., & Weil, M. (2018). Crystal structure of the thortveitite-related M phase, (Mn<sub>x</sub>Zn<sub>1-x</sub>)<sub>2</sub>V<sub>2</sub>O<sub>7</sub> (0.75 < x < 0.913): a combined synchrotron powder and single-crystal X-ray study.. Acta crystallographica. Section C, Structural chemistry, 74 (Pt 10), 1079-1087. https://doi.org/10.1107/s2053229618010458
The determination of the crystal structure of the M phase, (MnxZn1–x)2V2O7 (0.75 < x < 0.913), in the pseudobinary Mn2V2O7–Zn2V2O7 system for x ≈ 0.8 shows that the previously published triclinic cell parameters for this thortveitite related phase do not describe a true lattice for this phase. Instead, single-crystal X-ray data and Rietveld refinement of synchrotron X-ray powder data show that the M phase has a different triclinic structure in space group P-1 with Z = 2. As prior work has suggested, the crystal structure can be described as a distorted version of the thortveitite crystal structure of β-Mn2V2O7. A two-fold superstructure in diffraction patterns of crystals of M phase used for single crystal X-ray diffraction work arises from twinning by reticular pseudo-merohedry. This superstructure can be described as a commensurate modulation of a pseudo-monoclinic basis structure closely related to the crystal structure of β-Mn2V2O7. In comparison with the distortions introduced when β-Mn2V2O7 transforms at low temperature to α-Mn2V2O7, the distortions which give rise to the M phase from the β-Mn2V2O7 prototype are noticeably less pronounced.
Funding for this research was provided by: Royal Society (joint international exchange programme award to Anjan Sil); British Council, New Delhi (UKIERI project No. SA07-0052 to Kevin Knowles, Anjan Sil).
British Council in India (IND/CONT/07-08/E/180)
Royal Society (unknown)
External DOI: https://doi.org/10.1107/s2053229618010458
This record's URL: https://www.repository.cam.ac.uk/handle/1810/285655