C2H6

Ethane, with the chemical formula C2H6, is the second smallest alkane. It consists of two carbon atoms connected by a single C–C bond, with each carbon bonded to three hydrogens, giving a tetrahedral arrangement around each carbon (sp3 hybridization). The molecule is nonpolar and exists as a colorless gas at room temperature and pressure.

In terms of physical properties, ethane is a colorless, odorless gas at ambient conditions. It boils at −88.6 °C and melts at −182.8 °C. It is only sparingly soluble in water and more soluble in organic solvents; it is denser than air and highly flammable.

Ethane occurs naturally as a component of natural gas and is also produced during petroleum refining. It is separated from other gas constituents by cryogenic processing and used primarily as a feedstock for petrochemical production. The major industrial use of ethane is as a precursor to ethylene (C2H4) through cracking or steam cracking, providing a basis for the manufacture of plastics such as polyethylene.

Aside from its role as a chemical feedstock, ethane has other applications in some regional refrigerant systems (as refrigerant R-170) and can be used as a fuel or blending component in natural gas streams. Chemically, it is relatively unreactive at standard conditions but combusts with oxygen to yield carbon dioxide and water. It can undergo halogenation under radical conditions, and its C–C bond allows rotation, giving staggered and eclipsed conformations with a modest rotational barrier.

Safety considerations include its flammability and the potential to form explosive mixtures with air; it can also displace oxygen in enclosed spaces, necessitating proper ventilation and leak detection.