New polylodides of cesium containing double and triple decker cations, [Cs(benzo-18-crown-6)2]Ix and [Cs2(benzo-18-crown-6)3](Ix)2 (x=3, 5)

[Cs(b18c6)(2)]I-x (x = 3 (1), 5 (3)) and [Cs-2(b18c6)(3)](I-x)(2) (x = 3 (2), 5 (4)) (b18c6 = benzo-18-crown-6) have been synthesized by the reaction of benzo-18-crown-6 (C16H24O6), Cesium iodide (CsI) and iodine (I-2) in acetonitrile (1), ethanol/dichloromethane (2, 4) and 2-methoxyethanol (3). Their crystal structures were determined on the basis of single crystal X-ray data {(1): monoclinic, C2/c. Z = 4. a = 2048.8(5) b = 1329.5(5), c = 1588.7(5) pm, P = 110.23(1)degrees; (2): monoclinic, C2/c, Z = 4, a = 2296.0(1), b = 2092.7(1), c = 1373.6(1) pm = 100.21(1)degrees; (3): monoclinic, P2(1)/n Z = 4, a = 1586.3(1), b = 1745.5(1), c = 1608.6(1) pm, beta = 92.37(1)degrees; (4): triclinic, P (1) over bar, Z = 2, a = 1241.7(1), b = 1539.8(2) c = 1938.4(2) pm, alpha = 91.15(1) beta = 100.53(1), gamma = 95.26(1)degrees}. As expected, double decker cations centered by Cs atoms, [Cs(b18c6)(2)](+), are found in the structures of (1) and (3). In contrast, the triple decker cation found in (2) and (4) is less common. The triiodide anions of (1) and (2) can be regarded as normal and the chain-type pentaiodide anions of (3) and (4) fall into the known systematic sequence of these anions. The differences in the connectivity of the crystallographically independent I-5(-) anions in (4) are surprising with respect to the fact that, so far, independent pentaiodide anions do not show variations in their scheme of connectivity within one crystal structure.