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The crystal structure of Na4(UO2)(CO3)3 and its relationship to schröckingerite
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- Journal:
- Mineralogical Magazine / Volume 65 / Issue 2 / April 2001
- Published online by Cambridge University Press:
- 05 July 2018, pp. 297-304
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- Article
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Crystals of the compound Na4(UO2)(CO3)3 have been synthesized and the structure has been solved. It is trigonal with a= 9.3417(6), c = 12.824(1) Å, V = 969.2(1) Å3, space group P
c1 and Z = 4. The structure was refined on the basis of F2 (wR2 = 4.2%) for all unique data collected using Mo-Kα X-radiation and a CCD-based detector. The final R1 was 2.0%, calculated for 534 unique observed (Fo ≥ 4σF) reflections, and the goodness-of-fit (S) was 0.91. The structure contains a uranyl tricarbonate cluster composed of a uranyl hexagonal bipyramid that shares three equatorial edges with CO3 triangles. The uranyl tricarbonate clusters are connected through NaO6 and NaO5 polyhedra, forming a heteropolyhedral framework structure. This compound may be related to a uranyl carbonate phase with the same composition which has been reported as an alteration phase on the surface of Chernobyl ‘lava’, and as a mineral in the Jachymov ore district, Czech Republic.
