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acetylene (C2H2)





acetylene molecule
Bond lengths in the acetylene molecule
Also known as ethyne, a colorless, odorless, flammable gas prepared by the reaction of water and calcium carbide (or acetylide) and manufactured industrially by the cracking of petroleum fractions; it is a very weak acid. Acetylene is the first member of the alkyne series of hydrocarbons.

Acetylene may explode when under pressure, so is stored dissolved in acetone. When burned with oxygen, it produces extremely high temperatures, up to 3,480°C (6,300°F), and is therefore used in oxyacetylene torches for cutting and welding metals. It is also used in lamps, and in the synthesis of acetaldehyde, vinyl compounds, neoprene, rubbers, and various solvents and insecticides. In high concentration of 40 volumes per cent and higher it has the effect of an anesthetic.

Relative density: 0.625; melting point -80.8°C (-113.4°F); boiling point -84°C (-119.2°F).


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