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 separations > 1 Å are better described as dihydride complexes (see figure). The usual method for characterization is H NMR spectroscopy. The magnitude of spin-spin coupling, "J", is a useful indicator of the strength of the bond between the hydrogen and deuterium in HD complexes. For example, "J" is 43.2 Hz in HD but 33.5 Hz in W(HD)(CO)(PPr). Dihydrogen complexes typically have shorter H-spin-lattice relaxation times than the corresponding dihydrides. An ideal if nontrivial method of characterization of dihydrogen complexes is neutron diffraction. Neutrons interact strongly with hydrogen atoms, which allows one to infer their location in a crystal. In