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
I Should Have Known Better film, and it appears on the soundtrack. Capitol Records released "Something New" a month later with songs from the UK version of "A Hard Day's Night" that were not used in the film. The songs were also later released by Capitol on the "Hey Jude" compilation album in 1970. "I Should Have Known Better" was released as a single in a number of continental European countries, including Norway, where it reached number 1, and West Germany, where it reached number 6. In Sweden, the song topped the Kvällstoppen Chart for four weeks. The song is performed in the train compartment