The Doniach lattice gas (DLG) consists of a statistical model that can be mapped into a spin-1 Ising model with highly degenerate single-site states and the inclusion─using the nomenclature of the analogous magnetic model─of dipole-quadrupole interactions, besides the usual dipole-dipole, Zeeman-effect and crystal-field interactions. Its formulation was motivated aiming at the study of phase transitions in supramolecular structures of zwitterionic phospholipids, in particular, allowing an alternative description of density fluctuations in the system, already included in a certain class of lattice models (Nagle, J. F.