4',4',6',6'-Tetra-chloro-2-(6-methyl-pyridin-2-yl)-1H,2H-spiro-[naphtho-[1,2-e][1,3,2]oxaza-phosphinine-3,2'-[1,3,5,2,4,6]tri-aza-triphosphinine].

The title compound, C17H14Cl4N5OP3, is a spiro-phosphazene derivative with bulky naphthalene and pyridine rings. The phosphazene and the six-membered N/O rings are in flattened-boat and twisted-boat conformations, respectively. The naphthalene ring system and the pyridine ring are oriented at a dihedral angle of 18.06 (8)°. In the crystal, weak π-π stacking between the pyridine rings and between the pyridine rings and the naphthalene ring system [centroid-centroid distances = 3.594 (2) and 3.961 (2) Å, respectively] occur. Weak C-H⋯π inter-actions are also observed. These interactions link the molecules into a three-dimensional supramolecular network.