Properties of water by the IUPAC as being unsuitable for this purpose, since it is already the name of a cyclic ether also known as tetrahydropyran. The simplest systematic name of water is "hydrogen oxide". This is analogous to related compounds such as hydrogen peroxide, hydrogen sulfide, and deuterium oxide (heavy water). Using chemical nomenclature for type I ionic binary compounds, water would take the name "hydrogen monoxide" , but this is not among the names published by the International Union of Pure and Applied Chemistry (IUPAC). Another name is "dihydrogen monoxide", which is a rarely used name of water, and mostly used
Dihydrogen complex Dihydrogen complex Dihydrogen complexes are coordination complexes containing intact H as a ligand. The prototypical complex is W(CO)(PCy)(H). This class of compounds represent intermediates in metal-catalyzed reactions involving hydrogen. Hundreds of dihydrogen complexes have been reported. Most examples are cationic transition metals complexes with octahedral geometry. Upon complexation, the H−H bond is extended to 0.81–0.82 Å as indicated by neutron diffraction, about a 10% extension relative to the H−H bond in free H. Some complexes containing multiple hydrogen ligands, i.e. polyhydrides, also exhibit short H−H contacts. It has been suggested that distances < 1.00 Å indicates significant dihydrogen character, where