Preparation and structure of NaSr0.5Al2B2O7 and NaCa0.5Al2B2O7

1% Na doped into the intra- [Al2B2O7]2− double layer sites changes the CaAl2B2O7 structure (space group R3¯c) to the NaCa0.5Al2B2O7 structure (space group P63/m).