Synthesis of Alkaline-earth hexaborides, MB6 (MÂ =Â Ca, Ba, Sr), by a solid state metathesis (SSM) reaction

► A new synthetic pathway for alkaline-earth hexaborides has been developed. ► Alkaline-earth hexaborides could be used as overdopants in MgB2 superconductors. ► Several MgB2 + MB6 bulk composites were obtained. ► All compounds and bulks composites were characterized by XRPD and SEM methods.