The crystal structure ofp-chloriodoxybenzene

Abstract

Para-chlor-iodoxy benzene (ClC6H4IO2) is monoclinic. The cell, containing four molecules, has the dimensions a= 14.4 A., b = 6.50 A., c = 8.11 A. and β = 98½°. The space group is P21/c. The method of triple Fourier series has been applied to determine the electron density in a series of planes parallel to the ab plane. The plane containing the iodoxy group is very nearly perpendicular to the plane of the benzene ring. The I—O distances are nearly equal, being 1.60 and 1.65 A., with the angle O—I—O = 103°. The I—C distance is 1.93 A., the C—Cl distance is 1.80 A., and the benzene ring is a regular hexagon of side 1.41 A. The closest approach between I and O in adjacent molecules is 2.72 A., that between I and I is 3.60 A., that between Cl and C1 is 3.75 A., and that between CH and CH is 3.9 A. The main binding forces in the crystal are evidently between neighbouring iodoxy groups.