Isolated versus Condensed anion Structure V: X-ray structure analysis and Br-81 NQR of t-butylammonium tribromocadmate(II)-1/2 water, i-propylammonium tribromocadmate(II), and tris-trimethylammonium heptabromodicadmate(II)

The crystal structures of the condensed bromacadmate anions with chains bui lt of [CdBr3](infinity) were determined by X-ray structure analysis at 300 K. In addition, the temperature dependence of the Br-81 NQR frequencies was observed. [(t-C4H9NH3)CdBr3](2)-H2O (1) crystallizes with a double Br brid ged chain (monoclinic, P2/c, Z = 4, a = 1963.4(8), b = 887.7(4), c = 1432.1 (6) pm, and beta = 110.66(2)degrees). Six Br-81 NQR lines are observed at t emperatures between 77 and 330 K. (i-C3H7NH3)CdBr3 (2) crystallizes with a triple Br bridged chain (orthrhombic, Pbca, Z = 8, a = 1975.4(6), b = 1415. 8(4), c = 690.1(2) pm). (2) shows three Br-81 NQR lines at temperatures bet ween 77 and 193 K. A phase transition occurs at 224 K. The structure of [(C H3)(3)NH](3)Cd2Br7] (3) was redetermined. (3) consists of a triple Br bridg ed chain and a discrete [CdBr4] tetrahedron (hexagonal, P6(3)mc, Z = 8, a = 1483.5(2), c = 685.7(5) pm). The structure of (3) is identical to the one reported by Daoud, Ferret, and Dusausoy, Acta Crystallogr., B35, 2718 (1979 ). Three Br-81 NQR lines are observed at temperatures between 77 and 243 K.