K. Tsuda et al., Space group determination of the room-temperature phase of alpha '-NaV2O5 using convergent-beam electron diffraction, J PHYS JPN, 69(7), 2000, pp. 1939-1941
The space group of the room-temperature phase of alpha'-NaV2O5 has been det
ermined to be centrosymmetric Pmmn by convergent-beam electron diffraction,
which confirms the recent X-ray results. This result indicates that there
exists only one type of vanadium site assigned to V4.5+ at room temperature
.