M(benzo‐18‐crown‐6)I4 (M = Cd, Hg): Tetraiodide, Iodide–Iodine Adduct, or an Inclusion Compound of Iodine in MI2@(benzo‐18‐crown‐6)?

Abstract M(benzo‐18‐crown‐6)I 4 (M = Cd, Hg) are obtained as red columnar crystals from the reactions of benzo‐18‐crown‐6 (b18c6), cadmium and mercury iodide, respectively, and iodine in molar ratios of 1:1:2 in acetonitrile. They both crystallize with the orthorhombic crystal system, P2 1 2 1 2 1 , a = 833.7(1), b = 1610.9(1), c = 1846.8(1) pm, V = 2480.3(1) 10 6 ·pm 3 , Z = 4, for M = Cd and a = 823.4(1), b = 1616.5(1), c = 1866.1(1) pm, V = 2483.8(2) 10 6 ·pm 3 for M = Hg. The crystal structures consist of [M(b18c6)]I 2 molecules which are connected to a slightly lengthened iodine molecule via a secondary contact, according to the formulation I 2 @[MI 2 @(b18c6)].