Crystal structure and thermal-motion analysis of 4,4'-difluorobiphenyl

Abstract

The crystal structure of 4,4'-difluorobiphenyl has been determined at different temperatures between 155 and 293 K. This compound is isostructural with biphenyl (P21/a, Z = 2). We have carefully analysed the evolution of thermal motion by refining the translational and librational tensors. At any temperature, the molecules appear planar with a large librational amplitude around the long molecular axis and this amplitude remains slightly smaller than that observed in biphenyl. Crystal data at 293 K: C12HsF2, Mr = 190.2, a=7.78(1), b=5.847(9), c=9-99 (1) A, /3 =92.85 (9) °, V= 227 (2) A3, Dx = 1.386 g cm -3, A(Mo Ka) = 0.71073 A, R = 0.057 for417 reflections.