Colorless crystals existing in a few modifications. A lozenge modification occurs in nature as the mineral Thenardier m.p. 884 ° C and a density of 2,698g / cm3.
Na2SO4 – sodium sulfate [/ dt_quote] Sodium sulfate has the greatest solubility in water at 32,38 ° C of the aqueous solution is crystallized rhombic sodium sulfate, and below this temperature – monoclinic crystals with the composition and density Na2SO4.10H2O 1,464-1,481g / cm3.Na2SO4.10H2O occurs in nature as the mineral mirabilite, also called Glauber’s salt. Of a concentrated aqueous solution of sodium sulfate at 12 ° C was crystallized Na2SO4.7H2O, which at 23,5 ° C is converted to Na2SO4.
Sodium sulfate forms with different salts (Li2SO4, K2SO4, Na2SO3) solid solutions, and other sulfated double salts, some of which are found in nature, e. Na2SO4.MgSO4.4H2O (astrahanit), Na2SO4.CaSO4 (glauberit), Na2SO4.3K2SO4 (glazerit) and others.
Sodium sulfate is found in the waters of many lakes and seas. Sodium sulfate used in glass industry, in the production of kraft pulp, in the textile, leather and the soap industry, in ferrous metallurgy, for the production of Na2S, synthetic ultramarine, in medicine and veterinary.