Sodium tetraborate (Sodium tetraborate, borax, borax, borax, E285) gishiri ne na boric acid mai rauni da tushe mai karfi, fili na boron na kowa, yana da hydrates da yawa. Chemical formula Na2B4O7.
Ana amfani da sodium tetraborate a matsayin wani ɓangare na kayan wanka da kayan shafawa; a cikin takarda da masana'antun magunguna; a cikin samar da enamels, glazes, gilashin gani da launi; a matsayin disinfectant da preservative.