phosphanylidenes

Synonym: phosphinidenes
https://doi.org/10.1351/goldbook.P04549
Recommended name for carbene analogues having the structure RP: (former IUPAC name is phosphinediyls). A common non-IUPAC synonym is phosphinidenes.
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)