Resumen: The strontium chromium oxide [Sr2O2][CrO2]1.85 misfit layer compound has been synthesised at high pressure and high-temperature conditions. Electron diffraction patterns and high-resolution transmission electron microscopy images along [001] show the misfit character of the different layers composing
the structure with a supercell along the incommensurate parameter b=7b1=13b2. The modulated
crystal structure has been refined within the superspace formalism against single-crystal X-ray diffraction data, employing the (3+1)-dimensional superspace group Cnmb(0s20)0 0 s. The compound has a composite structure with lattice parameters a1=5.182(1)AËš , b1=5.411(1)AËš , c1=18.194(3)AËš for the first, SrO, subsystem and the same a and c, but with b2=2.925(1)AËš for the second, CrO2, subsystem. The layer stacking is similar to that of orthorhombic PbS(TiS2)1.18, but with a much stronger
intersubsytem bonding in the case of the oxide. The intersubsystem lattice mismatch is mainly handled by displacement modulations of the Sr atoms, correlated with modulations of the valence, the coordination and the anisotropic displacement parameters.
Palabras clave: misfit layer compounds, crystallography, high pressure
