Unsaturated

1. Capable of absorbing or dissolving to a greater degree; as, an unsaturated solution.
2. (Chem.) Capable of taking up, or of uniting with, certain other elements or compounds, without the elimination of any side product; thus, aldehyde, ethylene, and ammonia are unsaturated; benzene has three unsaturated bonds. The term is applied most commonly to compounds with a double or triple bond between two carbon atoms (as in ethylene).