It is colorless transparent liquid with specific gravity of 1.32. The boiling piont is 108.5°C. It has thrill smell, strong corrosiveness and poison. Fluosilicate acid volatilizes easily, cannot be made into anhydrous, the highest strength is 60.92%, but it is best stable when the strength is 13.3%. It doesn't decompose as distillation. It can erode glasses,pottery,aluminium and other metals. It has severe corrosive effect on skin, and is toxic to breathing apparatus of human.