Crystal and molecular structure of uranyl diperchlorate heptahydrate

The crystal and molecular structure of uranyl diperchlorate heptahydrate, UO2[ClO4]2·7H2O, has been determined by single-crystal X-ray methods. The crystals are orthorhombic, space group Pca21, with unit-cell dimensions a= 9.302(4), b= 14.692(6), and c= 10.842(5)Å, Z= 4. 493 Reflections have been measured by a diffractometer and the structure solved by heavy-atom methods to R 0.046. The crystal contains [UO2(OH2)5]2+,2[ClO4]–, and 2H2O in each asymmetric unit, held together by hydrogen bonds. The uranium has pentagonal-bipyramidal co-ordination with U–O(uranyl) of 1.71 Å(average), U–O(aqua) of 2.45 Å(average), and O ⋯ O contacts of 2.88 Å.