Sodium Sulfate

sodium sulfate

[′sōd·ē·əm ′səl‚fāt]

(inorganic chemistry)

Na₂SO₄ Crystalline compound, melts at 888°C, soluble in water; used to make paperboard, kraft paper, glass, and freezing mixtures.

McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Sodium Sulfate

 

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.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.