Alkylammonium lead halides. Part 1. Isolated PbI64− ions in (CH3NH3)4PbI6•2H2O

Abstract

The yellow (CH3NH3)4PbI6•2H2O(P21/n, a = 10.421(3) Å, b = 11.334(2) Å, c = 10.668(2) Å, β = 91.73(2)°, Z = 2) contains isolated PbI64− octahedra, CH3NH3+ cations of two types and H2O molecules. The cations and the water molecules are hydrogen-bonded to form [Formula: see text] units arranged in centrosymmtric [Formula: see text] pairs; the centres of these composite units and the Pb atoms form a distorted NaCl-type lattice. The Pb—I bond lengths in the PbI64− anions are compared with those in [Pb(II)I6]ε complexes containing shared I atoms and the effect of the sharing on the bond lengths is discussed. A scheme is proposed for the extensive three-dimensional hydrogen bonding in the structure.