Answer: strontia

AnswerCrossword Clue
strontiawhite, slightly water-soluble powder, Sr(OH)2, or its crystalline octahydrate (strontium hydrate): used chiefly in the refining of beet sugar
strontiawhite or grayish-white, amorphous powder, SrO, resembling lime in its general character: used chiefly in the manufacture of strontium salts