A new bond from an old molecule: formation, stability, and structure of P4H+

The formation, structure and vibrational frequencies of the tetraphosphorus molecule, P4, were examined by Fourier transform ion cyclotron resonance mass spectroscopy using proton transfer equilibrium techniques. Ab initio molecular orbital calculations were performed to determine the geometries of P4 and a protonated species P4H+ at the G2 level of theory. The results of experimental and quantum mechanical treatment revealed a novel kind of chemical bond in P4H+. Further analysis of this bond showed a symmetrical and covalent linkage.