Effect of Terminal Groups on Formation of Crystal Structure in α,γ‐Disubstituted n ‐Alkanes

The crystal and molecular structure of 1,16‐dibromohexadecane have been determined by X‐ray diffraction. Crystal data; empirical formula, C 16 H 32 Br 2 , formula weight M r = 384.24, monoclinic, P2 1 /a, a = 31.00(2), b = 5.38(1), c = 5.48(1) Å, β = 90.8(2)°, V = 914(3) Å 3 , Z = 2, D x = 1.396 g/cm 3 , δ(CuKα) = 1.5418 Å, μ(CuKα) = 55.41 cm −1 , F (000) = 396.00, T = 293 ± 1 K, wR = 0.082, R = 0.054 for 940 unique reflections [ I > 3.00σ( I )]. The molecular skeleton has an all trans zigzag hydrocarbon chain. The crystal has a layer structure, but the directions of molecular axes in neighbouring layers alternate. This molecular packing resembles to that of 1,16‐hexadecanediol, whereas n ‐alkanes or α‐monosubstituted n ‐alkanes do not appreciably have these molecular arrangement. The effect of terminal groups at both ends of α,ω‐disubstituted n ‐alkanes on the crystal structure is discussed.