Crystal Structures of Three Framework Alkali Metal Uranyl Phosphate Hydrates

✍ Scribed by Andrew J. Locock; Peter C. Burns

• Publisher: Elsevier Science
• Year: 2002
• Tongue: English
• Weight: 656 KB
• Volume: 167
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.2002.9646

✦ Synopsis

Three homeotypic hydrated alkali metal uranyl phosphates, A 2 (UO 2 )[(UO 2 )(PO 4 )] 4 (H 2 O) 2 , A=Cs (CsUP), Rb (RbUP), K (KUP), were synthesized by hydrothermal methods. Intensity data were collected at room temperature using MoKa radiation and a CCD-based area detector. Their crystal structures were solved by Patterson (CsUP) and direct (RbUP, KUP) methods and refined by full-matrix least-squares techniques to agreement indices (CsUP, RbUP, KUP) wR 2 ¼ 0:048; 0.230, 0.072 for all data, and R1 ¼ 0:023; 0.078, 0.038 calculated for 5338, 4738, 4514 unique observed reflections (jF o jZ4r F ), respectively. The compound CsUP is orthorhombic, space group Cmc2 1 , Z ¼ 4; a ¼ 14:854ð1Þ; b ¼ 13:879ð1Þ; c ¼ 12:987ð1Þ ( A, V ¼ 2677:5ð3Þ ( A 3 . Both RbUP and KUP are monoclinic, space group Cm, but are presented in the unconventional pseudo-orthorhombic space group Fm11 to facilitate comparison with CsUP and to allow a model for RbUP that includes the effects of pseudomerohedral twinning. RbUP is monoclinic, space group Fm11,