Synthesis and characterization of Eu2+ activated X12Al10.6Si3.4O32Cl5.4 (X=Sr,Ca) phosphors

► X12Al10.6Si3.4O32Cl5.4:Eu2+ (X=Sr,Ca):Eu2+ phosphors were prepared by the combustion method. ► X12Al10.6Si3.4O32Cl54 (X=Sr,Ca):Eu2+ shows emissions at 589 nm, 592 nm, and 617 nm under 254 nm excitation. ► At 354 nm X12Al10.6Si3.4O32Cl54:Eu2+ phosphors show broad-blue emission at 432 and 435 nm. ► Prepared phosphors show poor thermal stability at 1073 K and 1273 K.