Materialization nature : It is colourless, tasteless, the needle form without bad smell or the crystallization in post form of arris . It is apt to dissolve it in water and liquid ammonia. Apt to pick up the moisture, the relative humidity in the air is large when the picking up the moisture of urea is clicked, it right away absorb the moisture content of air and deliquescence. When temperature is higher than 130¡ãC, the aqueous solution will be divided into the ammonia and carbon dioxide directly.