|a chain of atoms in a molecule that is not joined at its ends into the form of a ring|
|the offspring of a zebra and a donkey.|
|an arrangement of five objects, as trees, in a square or rectangle, one at each corner and one in the middle.|
An arrangement of atoms of the same type that does not form a ring. Aliphatic compounds, such as ethane and isopropyl alcohol, are open-chain compounds.