Phosphinidenes (phosphanylidenes) (RP) are electronically and coordinatively unsaturated phosphorus compounds, which, as six-electron species, are formally analogous to the more familiar carbenes and nitrenes. In contrast to carbenes (CR 2 ), the extremely reactive phosphinidenes cannot be isolated without decomposition. Thus, our knowledge on phosphinidenes is mainly limited to trapping reactions and quantum-chemical calculations. There are a number of synthetic methods for phosphinidenes available, for example photolysis or thermolysis of cyclic phosphanes and oligophosphanes,