phosphorus hydride (IUPAC name: phosphane) is a colorless, toxic, highly flammable, and spontaneously combustible gas. It is a phosphorus ion, with the oxidation number of its atoms being 2
The chemical formula of PH3 is PH3H2, and PH2 is substituted by an alkyl halide containing a methyl group, or a nitro group. It is a major industrial fumigant used in the treatment of grain and also as a biocide.
PH3 can be prepared from elemental phosphorus or by the reaction of phosphorus trichloride with sodium and alkyl halides. By this method, a large number of volatile and nonvolatile primary and secondary alkyl phosphides are obtained with fair to good yields.
These compounds are largely structurally and chemically similar to the hydrides of the other main groups, but differ in their electron-pair and molecular geometries. This is because in a phosphorus hydride, the hydrogen atoms have been replaced by a phosphate ion, thereby increasing the bonding potential of the phosphorus molecule.
Another group of hydrides, the boron hydrides, are characterized by their unique chemical bonding schemes. These hydrides form complexes with various other elements, including oxygen, nitrogen, and sulfur.
Boron hydrides are very stable, exhibiting a range of spectroscopic features. Compared to carbon, silicon and phosphorus hydrides, they are relatively inert. They are the fourth most extensive class of hydrides, and have a variety of interesting chemistry and structures.
Superconductivity has recently been observed at low temperature in a two-dimensional superconducting phase, composed of layers of fluid hydrogen molecules that minimize Coulomb repulsion between the 2D sheets. This phase might be the source of the 83 GPa superconductivity measured in compressed “phosphine.”