The ammonium bromomercurates(II) (NH4)Hg5Br11 and (NH4)(4)HgBr6

The crystal structures of two ammonium bromomercurates(II), (NH4)Hg5Br11 (1) and (NH4)(4)HgBr6 (2), were determined from single-crystal X-ray diffraction data: 1: monoclinic, C2/m (no. 12), a = 1231.3(3), b = 1517.4(3), c = 680.4(2) pm, beta = 118.78(2)degrees, Z = 2, R-1 = 0.0391 for I-0 > 2 sigma(I-0); 2: tetragonal, P4/mnc (no. 128), a = 925.6(1), c = 887.2(1) pm, Z = 2, R-1 = 0.0370 for I(0 >)2a(I-0). According to (NH4)Br[HgBr2](5) and (NH4)(4)Br-4[HgBr2] they both contain [Br-Hg-Br] molecules. Additional bromide ions are only loosely attached to the mercury atoms, however involved in (NH4)(+)-Br- bonding.