salt10H2O

Salt10H2O is a descriptive term used for a salt that includes ten water molecules in its crystalline structure, i.e., a decahydrate. The best-known example is sodium sulfate decahydrate, Na2SO4·10H2O, commonly referred to as Glauber’s salt. The designation is not a strict IUPAC name but a shorthand used to indicate hydration level in hydrates.

In decahydrate form, water molecules are integral parts of the crystal lattice rather than free solvent. Such salts typically crystallize as white, crystalline solids and are soluble in water. Na2SO4·10H2O specifically forms readily from aqueous sodium sulfate solutions under suitable conditions and can exist stably at ambient temperatures in dry environments.

These decahydrates exhibit notable thermal behavior: upon heating to about 32 °C, Na2SO4·10H2O loses its water of crystallization and converts to the anhydrous salt Na2SO4. This dehydration is reversible; cooling in the presence of water allows rehydration to Na2SO4·10H2O. This dehydration–rehydration cycle is a characteristic feature of decahydrates and is of interest in phase-change or thermal storage discussions.

Historically, Glauber’s salt has been used as a laxative and has appeared in various chemical and industrial contexts. In modern practice, it serves mainly as a laboratory reagent and a source of sulfate, with safety considerations typical of inorganic salts: low toxicity in general, but ingestion in large amounts can cause gastrointestinal disturbances. Standard chemical hygiene applies when handling hydrated sulfates and their anhydrous forms.