Equilibrium relations in the system TiO2/V2O5/P2O5 and crystal structure of a NASICON-related vanadyl(V) titanium(IV) phosphate

► Equilibrium relations for the subsolidus have been established for the system TiO2/V2O5/P2O5. ► Phase formation has been monitored by XRPD as well as by 31P- and 51-MAS-NMR. ► A solid solution Ti(P1−xVx)2O7 exists up to x=0.43 with a miscibility gap at 0.23≤x≤0.30. ► The crystal structure of the new NASICON-related phosphate (VVO)TiIV6(PO4)9 is reported. ► The crystal structure contains the unprecedented [(V=O)O3] group.