Mercury is the scond most toxic element on the planet. It is most commonly know as in its silver liquid form but it also has many other forms. In its elemental form it is extremely volatile and can be found in the gas phase, a liquid, or at sufficiently low temperatures, as a solid. The majority of mercury released into the atmosphere is as a result of burning fossil fuels. Since the industrial age mercury being released has increased. The density of mercury is 13.5 ml-1.