The propagation of longitudinal waves in a weakly ionized gas consisting of three species of particles (neutrals, ions, and electrons) is analyzed giving full consideration to the influence of collisions between all three kinds of particles. The calculations are based on Euler's and Poisson's equations. Damping and phase constants for the neutral‐particle wave, the ion wave, and the electron wave are presented for different values of particle densities and for frequencies lower than, or comparable to the plasma frequency of the ions. The main result of the calculations is that in a certain frequency range the damping of the ion wave can be smaller than the damping of the neutral‐particle (sound) wave. This suggests the stimulation of ion waves by means of acoustic transmitters. Such an ion wave would be free of the potentially disturbing neutral‐particle wave at some distance from the source. This method would make it possible to stimulate a purely longitudinal plane wave.