Crystal and molecular structure of tetra(pentafluorophenyl)cyclotetraphosphane

Abstract

The structure of tetra(pentafluorophenyl)cyclotetraphosphane, (PC₆F₅)₄, has been determined by single-crystal X-ray diffraction methods. Data were collected on a linear diffractometer and refined by least-squares methods to a final R of 0·049 for 2186 reflections. The crystals are monoclinic, space group C2/c with a= 21·426, b= 7·627, c= 18·826 Å, β= 120° 27′, Z= 4. The presence of a four-membered phosphorus ring is confirmed and the molecule possesses a twofold symmetry axis in the solid state. The phosphorus ring is non-planar and has the approximate symmetry 2m(D_2d) with P–P 2·236 Å and |P–P–P–P| 32·18°. The C₆F₅ groups are in ‘equatorial’ positions and are nearly planar. The average phosphorus–carbon bond length is 1·838 Å.