The saturated hydrides of tervalent phosphorus having the general formula $\ce{P_{n}H_{n+2}}$. Individual members having an unbranched phosphorus chain are named phosphane, diphosphane, triphosphane, etc. The name of a saturated hydride of phosphorus wherein one or more phosphorus atoms have a bonding number of 5 is formed by prefixing locants and \(\lambda ^{5}\) symbols to the name of the corresponding phosphane. Hydrocarbyl derivatives of $\ce{PH3}$ belong to the class phosphines.