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 SẢN XUẤT TÚI GIẤY Máy sản xuất túi giấy cuộn – túi purchasi