A salt metathesis reaction (from the Greek μετάθεσις, "transposition"), sometimes called a double replacement reaction or double displacement reaction, is a chemical process involving the exchange of bonds between two reacting chemical species, which results in the creation of products with similar or identical bonding affiliations. This reaction is represented by the general scheme: A-B + C-D → A-D + C-B The bond between the reacting species can either be ionic or covalent. Classically, these reactions result in the precipitation of one product. In older literature, the term double decomposition...

Wadi El Natrun (Arabic for "Natron Valley"; Coptic: Ϣⲓϩⲏⲧ Šihēt "Measure of the Hearts", Greek: Σκῆτις or Σκήτη) is a valley located in Beheira Governorate, Egypt, including a town with the same name. The name refers to the presence of eight different lakes in the region that produce natron salt. In Christian literature it is usually known as Scetis (or Skete; Σκήτις, Σκέτη in Ancient Greek) and is one of the three early Christian monastic centers located in the desert of the northwestern Nile Delta. The other two monastic centers are Nitria and Kellia. These three centers are often easily confused...