Glutaraldehyde is an organic compound with the formula (CH2)3(CHO)2. The molecule consists of a five carbon chain doubly terminated with formyl (CHO) groups. It is usually used as a solution in water, and such solutions exists as a collection of hydrates, cyclic derivatives, and condensation products, several of which inter-convert. Because the molecule has two carbonyl group is reactive to primary amine groups (even as its hydrates), it can function as a cross-linking agent for any substance with primary amine groups and develop imine connected links.