The first seven-coordinate phosphorus compound, the hydrochloride salt of tris(8-dimethylaminonaphthyl)-phosphane, is reported as a tricapped tetrahedron with the nitrogen atoms acting as the capping ligands. It was synthesized from the reaction of N,N-dimethyl-1-naphthylamine with butyllithium followed by treatment with phosphorus trichloride. Three carbon atoms, three nitrogen atoms, and a proton surrounded the phosphorus atom.