Powder diffraction study of the crystal structure oftrans-Pd(NH3)2Cl2

Trans-Pd NH3)2Cl2 was studied by powder diffractometry. The unit cell parameters are a = 6.5408(8), b = 6.8573(8), c = 6.3574(6) A, a = 103.303(5), Β = 102.457(3), γ = 100.612(4); V = 262.63 A3, Z = 2, space group\(P\bar 1\). The atomic coordinates were established from Patterson syntheses and refined by the Rietveld method: Rp = 10.7%, Rwp = 10.2%, Rexp = 5.6%, RB = 3.6%. The crystal structure is of molecular type. The planar trans-Pd(NH3)2Cl2 molecules are packed parallel to each other into columns along the z axis, with every next molecule rotated through an angle of ∼ π/2. The observed packing of columns reproduces the cis-isomer quite closely. The structure has a disordering at 0.1Pd positions at 1/2, 0, 0 and 1/2 1/2, 0. A possible explanation for the nature of additional positions is offered.