MODEL RELEASED: Low-temperature chemistry. A chemist pouring liquid nitrogen around a reaction vessel during an experiment in low-temperature chemistry. The yellow liquid in a delivery flask (centre) is one of the reagents. To the left of this is a dessicating column. This allows air into the reaction vessel, but removes the water vapour with silica gel and by condensation. At far left is a cylinder of anhydrous ammonia gas. Nitrogen is liquid below 77.4 Kelvin (minus 195.7 Celsius), and is the most common cryostatic coolant used in laboratories.