The aqueous solubility of the least soluble salts in mixtures of sodium hydrogen succinate, sodium succinate, sodium hydrogen glutarate, and sodium glutarate with and without ammonium sulfate present has been studied. Solubility temperatures were determined in solutions of known concentration using Differential Scanning Calorimetry. The identity of the least soluble solid was determined by a combination of X-ray crystallography and infrared spectroscopy. The identified solids included ammonium sulfate, sodium sulfate, sodium ammonium sulfate dihydrate (lecontite), sodium hydrogen succinate, sodium succinate hexahydrate, sodium hydrogen glutarate dihydrate, and ammonium hydrogen glutarate. Of the 16 series of solutions studied, lecontite was most frequently the least soluble solid. (C) 2018 Elsevier Ltd.