The complete molecule of the title compound, C40H28N3O10P3, is generated by crystallographic twofold symmetry, with one P and one N atom lying on the rotation axis. The central P3N3 ring is close to planar, with an r.m.s. deviation of the six fitted atoms of 0.077 Å. The 2,2′-biphenoxy moiety generates a seven-membered spirocyclic structure with an endocyclic C—C—C—C torsion angle about the central biphenoxy C—C bond of 38.5 (4)°. The formyl-substituted phenyl rings subtend dihedral angles of 56.83 (10) and 61.02 (13)° with respect to the phosphazene core. The C=O and C—H groups of the formyl groups are disordered over two orientations in a 0.640 (4):0.360 (4) ratio. No directional interactions beyond normal van der Waals contacts could be identified in the crystal.
