M r= 380.4, monoclinic, P21/e, a= 19.836(3), b=5.450(1), c=24.068(3)A, fl= 128.37 (15) °, V= 2040 (4) A 3, Z=4, Din= (flotation) = 1.23, D x = 1.23 gcm -3, 2(Cu Kct) = 1.54178 A, g = 6.6 cm -1, F(000) = 808, T= 298 K, R = 0.055 for 875 observed independent reflections. The independent structural unit is formed by two crystallographically unrelated half-molecules. Both crystallographically independent molecules assume an almost planar conformation, the phenyl rings being slightly rotated with respect to the average molecular plane.