Ammonium dilead chloride

Abstract

Abstract.NH4Pb2C15, monoclinic, P2~/c, a = 9-018 (3), b = 7.981 (6), c = 12.502 (4)A, /~ = 90.09(2) ° , Z=4, Dc=4.50 g cm -3. NH4Pb2CI5 adopts the same structure as PbU2Se 5. This structure could be assigned to a number of other halides in the series AB2X 5 with A = K, Rb, TI or NH4; B = Pb or Sr and X = CI or Br.Introduetlon. Jansen (1968) reported the unit-cell dimensions of a series of compounds AB2X 5, with A = K, Rb or NH4; B = Pb or Sr and X = CI or Br. In this series a tetragonal modification with I4/mcm symmetry occurs (Poweli & Tasker, 1937) which is an ordered version of the Cr5B 3 (anti-) type structure (Bertaut & Blum, 1953). The other modification gave powder X-ray diagrams which could be indexed on the basis of an orthorhombic unit cell (Jansen, 1968). The systematic extinctions hk0: h = 2n and 00l: l=2n, however, do not fit an orthorhombic space group. The lattice constants of this modification are comparable with those of U3Se 5 (Moseley, Brown & Whittaker, 1972), if the difference between the ionic radii of Se 2-, and C1-and Br-is taken into account. Cation substitutions in the U3Se 5 structure lead to a structure with Pnma symmetry (Jeitschko & Donohue, 1975) and to one with P2~/c symmetry (Potel, Brochu & Padiou, 1975). In order to distinguish between the two possibilities it is sufficient to look for the occurrence of reflexions Okl: k + l = 2n + 1, which are forbidden in Pnma. In this way P2~/c symmetry could be assigned to this modification. statistics. Nearly half the reflexions had I < 2o(I) and were considered non-significant. Absorption corrections were applied with a computer program written by de Graaff (1973). The transmission factors ranged between 0.37 and 0.46 (p = 380 cm-l). Together with the absorption corrections new standard deviations were computed, taking into account the inaccuracy of the absorption correction and the attenuation factors, leaving 183 5 independent observed reflexions.The intensities were reduced to F values and a Wilson (1942) plot was calculated, yielding approximate values for the scale factor and the initial overall isotropic thermal parameter B.All crystallographic calculations were carried out on the Leiden University IBM 370/158 computer, with a set of computer programs written or modified by Rutten-Keulemans and de Graaff. Atomic scattering * NH 4 has an isotropic temperature factor of 0.7 (2) A 2.

Crystal structure of lead chloride thiocyanate, PbCl(SCN)

“…This environment is very similar to the one observed in BaCl(SCN) where the cation is located at the centre of a tricapped trigonal prism [1]. Among lead compounds, the present environment is not unusual: a mono-or a bicapped trigonal prismatic arrangement is observed in several chlorides or bromides as NH 4Pb2Cl5, NH4Pb2Br5 or [Co(NH3)6](Pb4Cl11) [2][3][4]. This shows that the lone pair effect is very weak in the chemistry of Pb(II) compounds, even with electronegative ligands.…”

Crystal structure of lead chloride thiocyanate, PbCl(SCN)

“…This environment is very similar to the one observed in BaCl(SCN) where the cation is located at the centre of a tricapped trigonal prism [1]. Among lead compounds, the present environment is not unusual: a mono-or a bicapped trigonal prismatic arrangement is observed in several chlorides or bromides as NH4Fb2Cl 5 , NH4Pb2Br 5 or [Co(NH3)6](Pb4Clii) [2][3][4]. This shows that the lone pair effect is very weak in the chemistry of Pb(II) compounds, even with electronegative ligands.…”

Structures and Ionic Transport Properties of Perovskite-Related BIAIIX3 and BIA2IIX5 Halides

“…A better way to do so is using structure field diagrams in which the stability of perovskites and related structures are mapped according to their ionic radii quotients. This was already done by Beck et al and Schilling and Meyer, who gave a comprehensive overview of several ABX 3 − and A I B 2 II X 5 / B I A 2 II X 5 ,,,,− halides and showed the correlation of the different structure types with the ratio of the ionic radii quotients r ( A )/ r ( X ) and r ( B )/ r ( X ), as depicte...…”