Oxide copper, so it displaces copper (II) oxide to form zinc oxide: Apart from metals, hydrogen can also displace metal oxides to form hydrogen oxide, also known as water: Since metals that are reactive form oxides that are stable, some metal oxides must be electrolyzed to be reduced. This includes sodium oxide, potassium oxide, calcium oxide, magnesium oxide, and aluminium oxide. The oxides must be molten before immersing graphite electrodes in them: Oxides typically react with acids or bases, sometimes both. Those reacting only with acids are labeled basic oxides. Those reacting only by bases are called "acidic oxides". Oxides that
Dihydrogen complex agostic interaction that is displaced by the H. In other cases, H will displace anionic ligands, sometimes even halides. Treatment of chlorobis(dppe)iron hydride with sodium tetrafluorborate under and atmostphere of hydrogen is one example: Many metal hydrides can be protonated to give dihydrogen complexes: In such cases the acid usually is derived from a weakly coordinating anion, e.g., Brookhart's acid. In 1984, Kubas et al. discovered that the addition of H to the purple-colored species M(CO)(PR) gave a yellow precipitate of mer-trans-M(CO)(PR)(H) (M = Mo or W; R = cyclohexyl, iso-propyl). This result rapidly led to the discovery of a