CO₂

Carbon dioxide (CO₂) is a chemical compound composed of one carbon atom and two oxygen atoms. It is a gas at standard temperature and pressure and exists in its solid state as dry ice. It is a naturally occurring substance vital to life on Earth, and a greenhouse gas which insulates the Earth's surface by trapping some of the planet's infrared radiation. In terms of volume, it is the second-largest component of the Earth's atmosphere after nitrogen.