1,8-bis(dimethylphosphino)naphthalene: an unusual case of pseudosymmetry

The title compound, C14H18P2, crystallizes in the rare tetragonal space group P4(2)bc with two independent molecules, each of which displays crystallographic twofold symmetry. In both molecules, the proximity of the PMe2 groups leads to distortion, the main feature of which is the out-of-plane displacement of the P atom [by 0.378(5) and 0.297(6)Angstrom]. The structure displays a marked pseudosymmetry, with local inversion centres each relating four pairs of molecules.