Dilute electrostatically–Vstabilized aqueous solutions of hexa-acylated (C14) lipid A-diphosphate from Escherichia coli were prepared with low polydispersities in shape, size and charge. A high degree of ordering was exhibited for volume fractions between Φ ≅ 1.5 × 10−4 and 3.5 × 10−4. The structure factor S(Q) was strongly dependent on the particle number density, the nature of ions, e.g. Ca2+, Mg2+, K+, Na+ and H+, the effective colloidal charge (Z*), and the Debye screening length, k. The magnitude and position of the S(Q) peaks vary not only with counterions, e.g. Ca2+ or Mg2+, and concentration (nM to μM), but also with the order of their addition to the lipid A-dispersions. Different types of colloidal-crystal structures were obtained for Φ ≅ 3.5 × 10−4. The Ca2+ and K+ salts exhibited FCC type-lattices with a = 56.3 nm and 55.9 nm, whereas the Na+ and Mg2+ salts of lipid A-diphosphate formed BCC type-lattices with a = 41.5 nm and 45.5 nm, respectively.