Also found in: Dictionary, Thesaurus, Medical, Wikipedia.
sodium sulfate,chemical compound, Na2SO4. It is a white, orthorhombic crystalline compound at ordinary temperatures; above 100°C; it assumes a monoclinic structure, and above about 250°C; it assumes a hexagonal structure. Sodium sulfate is soluble in cold water and very soluble in hot water. It forms two hydrates; the decahydrate is Glauber's saltGlauber's salt,
common name for sodium sulfate decahydrate, Na2SO4·10H2O; it occurs as white or colorless monoclinic crystals. Upon exposure to fairly dry air it effloresces, forming powdery anhydrous sodium sulfate.
..... Click the link for more information. . Anhydrous sodium sulfate is found in nature as the mineral thenardite. The major commercial source of sodium sulfate is salt cake, a byproduct of the production of hydrochloric acid from sodium chloride (common salt) by treatment with sulfuric acid. It is obtained (with other chemicals) by evaporation of natural brines. It is also obtained as a byproduct of viscose rayon manufacture and in several other, less important ways. The principal use of sodium sulfate is in processing wood pulp for making kraft paper. It is also used in glass manufacture, textile dyeing, and synthetic detergents.
Na2SO4, a salt; colorless crystals. Occurs naturally as the mineral thenardite. Density, 2.698 g/cm3; melting point, 884°C. Solubility in water, 16.3 percent at 20°C and 29.8 percent at 100°C. Anhydrous Na2SO4 is stable at temperatures above 32.384°C; lower temperatures induce the crystallization of Na2So4·10H2O. In nature, this crystal hydrate forms the mineral mirabilite (Glauber’s salt). Double salts of sodium sulfate with other sulfates, such as astrakhanite, Na2SO4·MgSO4 · 4H2O, and glauberite, Na2SO4·CaSo4 are also known.
Large quantities of sodium sulfate are found in brine and in the bottom deposits of chloride-sulfate salt lakes and the gulf of Kara-Bogaz-Gol (USSR). The reaction 2NaCL + MgSO4⇆MgCl2 + Na2So4 takes place there upon a reduction in temperature. Sodium sulfate crystallizes in the form of mirabilite. Another method for the preparation of Na2SO4 is the reaction of NaCl and H2SO4 in special “sulfate” furnaces at 500°-55O°C, which also yields hydrochloric acid.
Sodium sulfate is used in glass-making, the manufacture of sulfate cellulose, soap-making, tanning, nonferrous metallurgy, and textile manufacture, as well as in medicine and veterinary science (as a laxative). Sodium bisulfate, NaHSO4, and sodium disulfate (pyrosulfate), Na2S2O7, are used in the same way as KHSO4 and K2S2O7.