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 cation i because of the effect of the nuclear hyperfine Hamiltonian. The nuclear hyperfine Hamiltonian can mix the rotational levels of g and u electronic states (called ortho-para mixing) and give rise to ortho-para transitions The dihydrogen ion is formed in nature by the interaction of cosmic rays and the hydrogen molecule. An electron is knocked off leaving the cation behind. Cosmic ray particles have enough energy to ionize many molecules before coming to a stop. In nature the ion is destroyed by reacting with other hydrogen molecules: The ionization energy of the hydrogen molecule is 15.603 eV. The dissociation energy