Iron(II) oxide III and forms insoluble hydroxides in water. Iron(II) oxide is used as a pigment. It is FDA-approved for use in cosmetics and it is used in some tattoo inks. It can also be used as a phosphate remover from home aquaria. Iron(II) oxide Iron(II) oxide or ferrous oxide is the inorganic compound with the formula FeO. Its mineral form is known as wüstite. One of several iron oxides, it is a black-colored powder that is sometimes confused with rust, the latter of which consists of hydrated iron(III) oxide (ferric oxide). Iron(II) oxide also refers to a family of related non-stoichiometric
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