Synthesis and thermal expansion behavior of Ba_1+x Zr₄P_6−2xSi_2xO₂₄ and Sr_1+xZr₄P_6−2xSi_2xO₂₄ systems

NaZr₂P₃O₁₂ (NZP) is emerging as an important family of a large number of isostractural compounds in which several members have demonstrated very low thermal expansion characteristics. Ba_1+xZr₄P_6−2xSi_2xO₂₄ and Sr_1+xZr₄P_6−2xSi_2xO₂₄ crystalline solutions are two such systems belonging to the NZP family. Here, we report the bulk thermal expansion and axial thermal expansion behavior of various compositions in these systems. The low expansion behavior of these materials is attributed to their unique crystal structure, which is framework open structure, and can accommodate numerous ionic substitutions at various lattice sites.