Materials Data on BaU(SiO4)2 by Materials Project
BaU(SiO4)2 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. Ba2+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Ba–O bond distances ranging from 2.98–3.24 Å. U6+ is bonded to six O2- atoms to form distorted UO6 octahedra that share corners with four equivalent SiO4 tetrahedra. There are a spread of U–O bond distances ranging from 1.83–2.27 Å. Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two equivalent UO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 41°. There are a spread of Si–O bond distances ranging from 1.62–1.64 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Ba2+, one U6+, and one Si4+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to one U6+ atom. In the third O2- site, O2- is bonded in a single-bond geometry to two equivalent Ba2+ and one U6+ atom. In the fourth O2- site, O2- is bonded in a linear geometry to two equivalent Si4+ atoms. In the fifth O2- site, O2- is bonded in a linear geometry to two equivalent Si4+ atoms.