An-Najah Staff

The crystals of 4-(4′-ethoxyphenylazo)phenyl heptanoate (C21H26N2O3) are triclinc, space group P[unk] with a = 7.935(3),b = 8.568(4), c = 16.216(4) Å, α = 73.61(3), β = 75.01(3), γ = 71.26(4)° and two molecules per unit cell. The structure was solved by direct method (MULTAN80) using 1922 observed reflections. The refinement by block-diagonal least-squares and Fourier methods gave R = 0.0457. The molecule is almost linear and planar. The angle between two phenyl rings is 15.02°. The pairs of molecules related by a centre of symmetry form an imbricated arrangement. The crystalline cohesion is a result of a large number of feeble dispersion forces and dipole-dipole interaction.