Abstract:
(C₆H₅)₂ TIBr C₁₂H₈N₂ crystallizes as colourless and transparent needled in the trigonal system, space group P3121 , with cell dimensions a = 10.013 ± 0.001, c = 18.387 ± 0.004 Å , V = 1596.6 (Å)³ , Dm = 1.89 gm.cm⁻³, Z = 3 formularunitcell and Dx = 1.93 gm.cm⁻³ The unitcell parameters were obtained from powdered sample using the Guinier-Hagg diffraction technique. The Weissenberg method was employed with Cu Kα radiation λ = 1.5418 Å to record 247 independent reflections on multiple films, and the intensities were measured visually. The absorption correction was made with the linear absorption µ Cu Kα = 168.7 cm⁻¹ for an approximately cylindrical crystal of r = 0.01 cm., l = 0.035 cm. The structure has been determined by the heavy-atom method, positional and isotropic thermal parameters were refined by the full-matrix least-squares method to a final R index of 0.111 .Tl and Br atoms are found to occupy special positions in the unitcell at 3a, 3band the rest in general positions of 6c. The Tl-Br bonds are coplanar with the Tl-N bonds spanning across the group C₁₂H₈N₂, whereas the (C₆H₅)₂ groups are both over and under the N-Tl-Br plane, respectively.