CsUV3O11, a New Uranyl Vanadate with a Layered Structure

✍ Scribed by I. Duribreux; C. Dion; F. Abraham; M. Saadi

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 227 KB
• Volume: 146
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1999.8349

✦ Synopsis

A new cesium uranyl vanadate CsUV 3 O 11 has been synthesized by solid state reaction. Its crystal structure has been determined from single-crystal X-ray di4raction data. It crystallizes in the monoclinic system with space group P2 1 /a and unit cell parameters a ‫؍‬ 11.904(2) A s , b ‫؍‬ 6.8321(6) A s , c ‫؍‬ 12.095(2) A s , ‫؍‬ 106.989(5)3, Z ‫؍‬ 4, and D exp ‫؍‬ 4.89(2) g/cm 3 . A full-matrix least squares re5nement yielded R ‫؍‬ 0.046 and R w ‫؍‬ 0.045 for 1831 independent re6ections with I > 3 (I) collected on a Nonius CAD4 di4ractometer (MoK radiation). The structure of CsUV 3 O 11 is characterized by [UV 3 O 11 ] layers parallel to the (001) plane. The layers, very similar to those found in UV 3 O 10 , are built up from VO 5 square pyramids sharing corners of their equatorial bases and UO 8 hexagonal bipyramids, the U atoms occupying the hexagonal holes created by the VO 5 array. The Cs ؉ ions are located between two successive layers and hold them together; the Cs ؉ ions and two layers constitute a neutral 99sandwich::

In this unusual structure, the neutral sandwiches are stacked one above another along the [104] direction with no formal chemical bonds between the neutral sandwiches. The Cs mobilities in CsUV 3 O 11 and Cs carnotite are compared.