False minima in X-ray structure solutions associated with a 'partial polar ambiguity': single crystal X-ray and neutron diffraction studies on the eight-coordinate tungsten hydride complexes, WPMesub(3)sub(4)Hsub(2)Xsub(2) (X = F, Cl, Br, I) and WPMesub(3)sub(4)Hsub(2)F(FHF)

Single-crystal X-ray diffraction techniques are used to gauge the molecular frameworks of the eight-coordinate tungsten hydride complexes W[PMesub(3)]sub(4)Hsub(2)Xsub(2) (X= F, Cl, Br, I) and W[PMesub(3)]sub(4)Hsub(2)F(FHF). Single-crystal neutron diffraction was also used to derive the molecular structure of another set of complexes. The structures of both complexes are similar. The results of the investigation are discussed.