<unk>  (chemical formula<unk>  is a<unk> lorless, odorless, tasteless, flammable gas that is slightly less dense than air.<unk> <unk> nsists of one<unk>  atom and one oxygen atom<unk> nnected by a triple bond. It is the simplest molecule of the oxocarbon family. In<unk> ordination<unk> mplexes the<unk>  ligand is called<unk> yl. It is a key ingredient in many processes in industrial chemistry. Thermal<unk> mbustion is the most<unk> mmon source of<unk> , however there are numerous environmental and biological sources that generate and emit a significant amount of<unk> .<unk>  is important in the production of many<unk> mpounds, including drugs, fragrances, and fuels. It is produced by many organisms, including humans. Upon emission into the atmosphere,<unk>  affects several processes that<unk> ntribute to climate change.<unk>  has important biological roles across phylogenetic kingdoms. In mammalian physiology,<unk>  is a classical example of hormesis where low<unk> ncentrations serve as an endogenous neurotransmitter (gasotransmitter) and high<unk> ncentrations are toxic resulting in<unk>  poisoning. It is isoelectronic with cyanide anion CN−.
Carbon monoxide
Nitrosamine
Mustard gas
Nicosan
Metaldehyde
Lewisite
Nitrous oxide 
Asbestos