Characteristic hydrogen bonding (H-bonding) patterns define secondary structure in proteins and nucleic acids. We show that similar patterns apply for α2-8 linked SiA (sialic acid) in H2O; and that H-bonds define its structure. A 15N,13C α2-8 SiA tetramer was used as a model system for the polymer. At 263K, we detected intra-residue through-bond J couplings between 15N and C8 for residues I, II and III of the tetramer, which indicate H-bonds between the 15Ns and the O8s of these residues. Additional J couplings between the 15Ns and C2s of the adjacent residues confirm the putative H-bonds. The NH groups showing this long-range correlation also experience slower 1H/2H exchange rate. Additionally, detection of couplings between H7 and C2 for residues II and III imply that the conformations of the linkers between these residues are different than the monomer's. These structural elements are consistent with two left handed helical models: 1) two residues per turn (24 helix) and 2) four residues per turn (14 helix). To discriminate between models, we resorted to 1H, 1H NOEs. The 24 helical model is in better agreement with the experimental data, for which all of the observed NOEs are predicted. On the other hand, for the 14 helix 87% of the observed intra-residue NOEs are predicted. In this report we provide direct evidence of H-bonding for a tetramer of α2-8 linked SiA and show how H-bonds can be a determining factor for shaping the carbohydrate three-dimensional structure.