CONTRIBUTIONS TO THE CHEMISTRY OF PHOSPHORUS .215. SIMPLE PREPARATION OF THE PENTAPHOSPHACYCLOPENTADIENIDE ION, CYCLO-P5-, BY DEGRADATION OF RED PHOSPHORUS WITH POTASSIUM DIHYDROGENPHOSPHIDE

The pentaphosphacyclopentadienide ion 1 is easily obtained in the form of a KP5 solution by the reaction of red phosphorus with potassium dihydrogenphosphide (1.9:1) in boiling dimethylformamide. The IR absorption at approximately nu = 815 cm-1 previously observed for NaP5/[18]crown-6/THF solutions is not to be assigned to 1. The formation of 1 in the degradation process of red phosphorus is discussed.