Strontium is usually a chemical component with symbol Sr and atomic range 38. An alkaline earth steel, strontium is actually a tender silver-white or yellowish metallic aspect that is very reactive chemically. The metal turns yellow when it's exposed to air. YttriumMÁY S?N XU?T TÚI GI?Y Máy s?n xu?t túi gi?y cu?n – túi purchasing – th?c ph