Crystal structures of Rb2U2O7 and Rb8U9O31, a new layered rubidium uranate

Two alkali metal uranates Rb2U2O7 and Rb8U9O31 have been synthesized by solid state reaction at high temperature and their crystal structures determined from single crystal X-ray diffraction data, collected with a three circles Brucker SMART diffractometer equipped by Mo(Kα) radiation and a charge-coupled device (CCD) detector. Their structures were solved using direct methods and Fourier difference techniques and refined by a least-square method on the basis of F2 for all unique reflections, with image for 53 parameters and 746 independent reflections with image for Rb2U2O7, monoclinic symmetry, space group P21/c, image, image, image, image, image, image, image and image for 141 parameters and 2065 independent reflections with image for Rb8U9O31, orthorhombic, space group Pbna, image, image, image, image, image, image.