The crystal structure of γ-P
4, one of three modifications hitherto reported on white phosphorus was determined from X-ray powder diffraction data collected at
T=123 K on a Guinier-Simon camera equipped with a cold gas blower and an image plate detector. The crystal structure of γ-P
4was solved by the method of simulated annealing, and the subsequent Rietveld refinement in the range 12°<2θ<92°employing rigid-body constraints on the P
4molecule converged at
Rp=3.8%, w
Rp=5.0%, and
RF2=14.0%. The asymmetric unit of γ-P
4contains three P atoms; two P atoms in a molecule are related by a mirror plane which bisects the molecule. The centers of gravity of these P
4molecules show a distorted body-centered cubic (bcc) arrangement. The four apices of the P
4tetrahedron point to the largest possible voids formed by neighbor molecules. The difference to the crystal structure of SiF
4and GeF
4with an exact bcc arrangement of tetrahedral molecules is discussed as well as, in terms of layer stackings, the similarity of the structures of γ- and β-P
4.
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