At a pressure of 5.07 MPa (50 atmospheres), carbon dioxide gas can be compressed into a colorless liquid. Liquid carbon dioxide has a density of 1.101 g/cm³ at -37°C; its boiling point is -88.5 ± 9.0°C (at 760 mmHg), and its melting point is -78.5°C.
When carbon dioxide dissolves in water, the water's pH level decreases, which poses a hazard to aquatic organisms.
Liquid carbon dioxide absorbs a significant amount of heat as it evaporates; when cooled to -21.1°C under a pressure of 0.415 MPa, liquid carbon dioxide solidifies to form solid carbon dioxide, commonly known as dry ice. Under normal conditions, carbon dioxide is chemically stable; however, at high temperatures, it decomposes into carbon monoxide and oxygen. When present alongside trace amounts of water, its aqueous solution exhibits acidic properties.
