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| Home > Publications database > Wadsley-related vanadium oxides under extreme conditions :incommensurate V0.92O2 with a peculiar modulated structure and unexpectedproperties |
| Home > Publications database > Wadsley-related vanadium oxides under extreme conditions :incommensurate V0.92O2 with a peculiar modulated structure and unexpectedproperties |
| Conference Presentation (Invited) | FZJ-2026-04488 |
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2026
Abstract: Wadsley vanadium oxides form a homologous series with general compositionVnO2n+1 between the end members α-V2O5 and VO2(B). They are oxygen deficientwith different ordered vacancies in an oxygen cubic close-packing array andexhibit a variety of crystal structures due to different polyhedra around the V4+and V5+ cations and polyhedral connectivity. Members of this series exhibit a richvariety of structural, electronic, magnetic, and metal–insulator phase transitions.Starting from the Wadsley-phase V6O13, corresponding to V0.92O2, we synthesizeda peculiar rutile-related phase at 10 GPa and 1273 K, which we subsequentlystudied with single-crystal X-ray diffraction. V0.92O2 starts to decompose at 470 Kand atmospheric pressure. When heated to temperatures above about 350 K, thematerial transforms to an incommensurate phase. Measurements of electronictransport properties provide evidence that the incommensurate phase is insulating.In the incommensurate phase, the oxygen sublattice is essentially rigid.Amplitudes of the displacive modulation of the V atoms are also hardlysignificant and V—V distances are almost constant. The absence of significantdisplacements of the atoms in the modulated structure is attributed to the fact thatthe atoms are disordered over several split atom positions. For the modeling, ananharmonic description of the displacement parameters and their correspondingmodulation was used for the V atoms to reach satisfactory agreement factors formain and first-order satellite reflections. On compression at room temperature,V0.92O2 reaches the ideal rutile structure at about 5.0 GPa.Our results show that the structural and electronic behaviour of V0.92O2 atextreme conditions is distinctly different from that of stoichiometric VO2 and thatsynthesis under extreme conditions can lead to new materials with unexpectedproperties and peculiar structural features.eferences[1] A . Grzechnik & K. Friese, CrystEngComm., 28, 2285, 2026.[2] A. Grzechnik et. Al., IUCrJ, 13, 116, 2026
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