Na2SO410H2O

Na2SO410H2O, commonly written as Na2SO4·10H2O, is the decahydrate form of sodium sulfate. It is widely known as Glauber’s salt and appears as a white, crystalline solid that dissolves readily in water. In this decahydrate form, ten molecules of water are integrated into the crystal lattice as water of crystallization.

At room temperature, the compound exists as the decahydrate, but it dehydrates upon heating. Around 32 °C, Na2SO4·10H2O loses its water of crystallization to form anhydrous sodium sulfate (Na2SO4). The anhydrous salt has a much higher melting point, about 884 °C. This dehydration around the ambient phase transition is a notable characteristic and underpins its use in phase-change applications for thermal energy storage.

In nature, the decahydrate is known as the mineral mirabilite and is typically found in cold environments or brine deposits. When exposed to higher temperatures, mirabilite dehydrates to thenardite, the anhydrous form of sodium sulfate.

Uses for Na2SO4·10H2O include historical and industrial roles. It has been used as a laxative due to its osmotic effect and has industrial relevance as a source of sodium sulfate for glass manufacturing and chemical processes. Its phase-change property near room temperature has attracted interest for latent heat storage materials in thermal regulation and energy storage applications.

Safety considerations are similar to other inorganic salts: it is of relatively low toxicity, but ingestion can cause laxative effects, dehydration, or irritation. Proper handling includes standard laboratory precautions, minimizing inhalation of dust, and storing away from incompatible substances.