Synthesis of the fibrous materials ρ-Na0.50H0.50TiOPO4 and ρ-K0.67H0.33TiOPO4 by reaction of ρ-Ti2O(PO4)2(H2O)2 with molten alkali nitrates

The reaction of ρ-TiP with molten MNO3 (M = Na, K) originates the formation of new metal phases, ρ-MxH1−xTiOPO4 (x = 0.50, M = Na; x = 0.67, M = K). These compounds maintain the fibrous morphology of their precursors. The processes occur in two differentiated steps with formation of ρ-MxH1−xTiOPO4 (x = 0.25, M = Na; x = 0.42, M = K) intermediate phases. An ion-exchange mechanism is proposed for the reaction. Thermal treatment of the novel fibrous alkali metal phosphates produces mixtures of MTiOPO4, MTi2(PO4)3, and TiO2.