Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT ICR) has revealed the existence of the P4Li+ ion as a stable species in the gas phase. High-level ab initio calculations show that P4Li+ appears as a 'planetary system' wherein the lithium cation can easily move around the P4 moiety along paths (or 'orbits') connecting the points above the middle points of the P-P edges with points above the center of the PPP faces, the movement toward the comers of the tetrahedron being the less favored. Due to symmetry, this orbiting is 4-fold degenerate.