P5X2+ (X = Br, I), a phosphorus-rich binary P-X cation with a C2v-symmetric P5 cage

Article abstract of DOI:10.1002/1521-3773(20011203)40:23<4406::AID-ANIE4406>3.0.CO;2-X

Insertion of the intermediately formed carbeneanaloguous PX₂⁺ ion (X = Br, I) into one of the P-P bonds of the P₄ tetrahedron led to the P₅X₂⁺ ion (see structure of the Br derivative)-the first example of the previously unknown class of phosphorus-rich binary P-X cations.