C2H2

C2H2 is the chemical formula for acetylene, also known as ethyne. It is the simplest member of the alkyne family, a hydrocarbon with a carbon–carbon triple bond. The molecule is linear, with one hydrogen attached to each carbon. The IUPAC preferred name is ethyne; acetylene is the common name.

In its pure form, acetylene is a colorless gas at room temperature. It is highly flammable and forms explosive mixtures with air under certain conditions. The gas is typically odorless, but commercial acetylene is often odorized with sulfur-containing compounds to help detect leaks. Acetylene has a relatively low boiling point, and it is usually stored under pressure as a stabilized solution in a solvent such as acetone, which helps prevent polymerization of the gas.

Industrial production of acetylene has historical roots in the reaction of calcium carbide with water: CaC2 + H2O → C2H2 + Ca(OH)2. It is also produced as a byproduct in some petrochemical processes. Because acetylene can polymerize explosively under high pressure or shock, it is stored and transported in specially designed cylinders that dissolve the gas in a stabilizing solvent and regulate pressure.

Applications of acetylene are broad. It is a key industrial feedstock for the synthesis of numerous organic chemicals and materials and has been widely used for welding and metal cutting in oxyacetylene equipment. In addition to metalworking, acetylene serves as a chemical building block for products such as acetaldehyde, acetic acid derivatives, and various polymers and intermediates.

Safety considerations are central to handling acetylene. It is highly flammable and can form explosive mixtures with air. Proper ventilation, leak detection, avoidance of ignition sources, and secure, certified storage in pressure-rated cylinders with appropriate stabilizers are essential to minimize risk.