The phase diagram of the binary system of barium and sodium n-butanoates has been studied by differential thermal analysis, hot stage polarization microscopy, and small angle X-ray diffraction. Pure barium n-butanoate exhibits a complicated thermal behavior : it melts at 519 It, then immediately solidifies, and remelts at a higher temperature (589 K). The addition of a second component like sodium n-butanoate stabilizes the liquid which appears with the first melting of barium n-butanoate. This melt exists up to the temperature of the second melting, which may be called the clearing point because this liquid has been found to be slightly anisotropic and to have local bilayer smectic order. The temperature and concentration ranges of formation of the liquid crystalline smectic A solutions has been established. These liquid crystalline solutions are formed as a result of the eutectic reaction at 425 K. In this binary system, glass formation has been discovered in the composition range 0 to 70 mol % of Na n-butanoate.