The brighter side of CO2
Carbon dioxide has the formula CO2 (the molecule is linear: O=C=O) and is produced with water when organic materials burn (wood, oil, coal, etc.). Since CO2 can absorb infrared radiation strongly, it is called a 'greenhouse' gas, helping to trap heat in the earth's atmosophere. This has earned CO2 a bad name for possibly contributing to global climate change. But under special conditions, CO2 can be forced into a state called a supercritical fluid , which behaves like both a liquid and a gas! Like a gas, it has ultra-low viscosity and can creep into tiny crevices and pores but, like a liquid, can still dissolve dirt, oils, etc. Supercritical CO2 is a great replacement for dry cleaners since it is nontoxic and safe for the ozone layer. This is just the tip of the iceberg. Because it is so inert and leaves no residues, supercritical CO2 is perfect for the food industry since it can be used in processes like decaffeinating coffee beans without affecting the flavor of the coffee. Inexpensive and non-flammable, supercritical CO2 is growing into one of the safest, and most environmentally friendly of all industrial solvents.