Phase equilibrium study of the system NaV2O5V2O3V2O5 at 923 K

The phase diagram of the system NaV2O5V2O3V2O5 at 923 K was established. Two new phases, δ-NaxV2O5(0.55 ≤ x ≤ 0.57) and NaxV12O29(0.55 ≤ x ≤ 0.65), were found. The δ-NaxV2O5 is hygroscopic and isostructural with δ-AgxV2O5. The NaxV12O29 is a member of a homologous series of compounds MxV6nO15n−m found also for M = Li or Cu. The dc conductivity of a single crystal of NaV6O11 was measured at 5–298 K.