Hydrazine Sulfate Polymorphic Modifications: Liquid Phase Crystallization and Some Properties

The formation of orthorhombic and monoclinic polymorphic modifications of hydrazine sulfate from an aqueous solution in the temperature range from 5 to 35°C was studied. A curve of the hydrazine sulfate solubility in water in the range of 5–25°C was obtained. It is shown that, with a decrease in the growth temperature, the mass fraction of precipitated monoclinic hydrazine sulfate crystals increases. A possible temperature-induced transition from the orthorhombic to the monoclinic modification was detected when cooling to the boiling temperature of liquid nitrogen.