New crystal data for ferroelastic isopropyl ammonium chloroplatinate and chlorostannate (IPACP and IPACS)

Two new ferroelastic compounds, isopropyl ammonium chloroplatinate (C₃H₇NH₃)₂PtCl₆ and isopropyl ammonium chlorostannate (C₃H₇NH₃)₂SnCl₆, studied at room temperature (23°C) with Laue, Weissenberg, powder X-ray diffraction and optical second-harmonic generation (SHG) techniques have probable space group P2₁/c (Bbcm above 37°C and 40°C respectively). The crystals are so strongly pseudo-orthorhombic (Bbcm) with prevalent twinning that the monoclinic character is not apparent in the X-ray powder pattern. Lattice parameters for the pseudo-orthorhombic cells are a= 11.589 (1), b= 19.024 (3), c = 7.237 (3) Å, for IPACP and a = 11.851 (7), b = 19.05 (1) and c = 7.227 (4) Å for IPACS.