Magnesium oxide Magnesium oxide Magnesium oxide (MgO), or magnesia, is a white hygroscopic solid mineral that occurs naturally as periclase and is a source of magnesium (see also oxide). It has an empirical formula of and consists of a lattice of Mg ions and O ions held together by ionic bonding. Magnesium hydroxide forms in the presence of water (MgO + HO → Mg(OH)), but it can be reversed by heating it to separate moisture. Magnesium oxide was historically known as magnesia alba (literally, the white mineral from magnesia – other sources give magnesia alba as MgCO), to differentiate it from "magnesia
Dihydrogen bond a protic acid and the borane end is hydridic. The resulting B−HH−N attractions stabilize the molecule as a solid. In contrast, the related substance ethane, HCCH, is a gas with a boiling point 285 °C lower. Because two hydrogen centers are involved, the interaction is termed a dihydrogen bond. Formation of a dihydrogen bond is assumed to precede formation of H from the reaction of a hydride and a protic acid. A very short dihydrogen bond is observed in NaBH·2HO with H−H contacts of 1.79, 1.86, and 1.94 Å. Protonation of transition metal hydride complexes is generally thought to occur