Granular Dry Ice

Dry has physical properties of white crystals that can easily sublimate at room temperature. Its high heat of vaporisation causes the surrounding temperature to fall rapidly when it sublimates at atmospheric pressure. Therefore, dry ice sublimation in the air can lead to liquefaction or even further condensation of water vapour in the air. This can result in the formation of water vapour droplets or small ice crystals adhering to the dust in the air, forming the visible white smoke. Dry ice has a simple cubic crystal structure and is a molecular crystal. Carbon dioxide molecules are located at the apex and centre of the cube in different orientations and accumulate to form dry ice crystals.

Dry ice is chemically stable, odourless, non-toxic, and non-combustible, and does not support combustion. However, elevated levels of carbon dioxide in the air can irritate the respiratory system, leading to accelerated breathing and a risk of asphyxiation (hypoxia). Carbon dioxide is highly thermally stable, with only 1.8% decomposition at 2000°C. Dry ice is an acidic oxide, and acidic oxides react with water to form carbonic acid.