phosphanes

https://doi.org/10.1351/goldbook.P04548
The saturated hydrides of tervalent phosphorus having the general formula PnHn+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 PH3 belong to the class phosphines.
Source:
PAC, 1995, 67, 1307. 'Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)' on page 1357 (https://doi.org/10.1351/pac199567081307)