Carbon dioxide
Molar mass: 44.01 g/mol · Class: Covalent oxide
Elements: carbon, oxygen
Structure
The molecule is linear, with carbon double-bonded to two oxygens (O=C=O). Although each C=O bond is polar, the symmetrical shape cancels the dipoles, so the molecule is nonpolar overall.
Properties
Colorless, odorless gas, denser than air
Dissolves in water to form weak carbonic acid
Solid form (dry ice) sublimes at -78.5 °C
Absorbs infrared radiation, contributing to the greenhouse effect
Applications
Carbonated drinks and fire extinguishers
Dry ice for cooling and special effects
Greenhouse enrichment to boost plant growth
Welding shielding gas
Non-toxic at normal levels, but dangerous in confined spaces: it displaces oxygen and causes suffocation without warning since it is odorless. Dry ice causes frostbite; never handle with bare hands or store in sealed containers.
Data source: IUPAC standard atomic weights 2021; molar mass computed from CO2