X-ray diffraction data for two new calcium uranium (VI) hydrates

Abstract

The X-ray powder diffraction patterns for two new synthetic calcium uranium (VI) silicate hydrate phases are reported. Ca1.5U6(OH)7O16·7H2O is orthorhombic, space groupP*a*, with unit cella=13.8949(14),b=12.0776(12),c=15.228(3) Å. The structure appears to be related to that of becquerelite. Ca2(UO2)2(Si2O5)3·10H2O was also indexed on an orthorhombic unit cell,a=12.075(3),b=15.406(6),c=26.043(6) Å. The Powder Diffraction File coverage of uranium-containing minerals which could, on the basis of their chemical formula, form in U-containing cements is also reviewed.