Phase Formation of Rubidium Bismuth Titanoniobates Based Solid Solutions

Abstract: The effect of the rubidium nitrate amount on the phase with Dion–Jacobson structure RbBi2Ti2NbO10 formation during solid-state synthesis was studied. It was found that the rubidium nitrate content from the stoichiometric amount to 50 mol % favors the formation of a phase with the Dion–Jacobson structure, and at a higher concentration of the salt precursor, the Aurivillius phase is predominantly formed. Moreover, when using a significant excess of rubidium nitrate, the possibility of layered perovskite phase transition from the Aurivillius family to the Dion–Jacobson phase was discovered with an increase in the heat treatment temperature. It is due to the volatility of the rubidium-containing component and the mobility of ions located between the BO6 octahedra in perovskite blocks (Bi3+ cations) and in the interlayer space (Rb+ cations). The introduction of excess rubidium nitrate does not significantly affect the unit cell parameters of solid solutions based on RbBi2Ti2NbO10, which also indirectly indicates the possibility of mutual migration of rubidium(I) and bismuth(III) cations between the positions occupied in the structure. The symmetry of the unit cell of the obtained phases belongs to the tetragonal syngony. An increase in the loss of the rubidium-containing component from 40 to 47% with an increase in the excess of the initial rubidium nitrate in the mixture is shown. © Pleiades Publishing, Ltd. 2025.