Materials Data on Ce2U2O9 by Materials Project
U2Ce2O9 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. U6+ is bonded in a distorted body-centered cubic geometry to ten O2- atoms. There are eight shorter (2.34 Å) and two longer (2.72 Å) U–O bond lengths. Ce3+ is bonded in a distorted q6 geometry to nine O2- atoms. There are a spread of Ce–O bond distances ranging from 2.35–2.51 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent U6+, two equivalent Ce3+, and one O2- atom to form a mixture of corner, edge, and face-sharing OCe2U2O tetrahedra. The O–O bond length is 2.44 Å. In the second O2- site, O2- is bonded in a 2-coordinate geometry to four equivalent U6+, two equivalent Ce3+, and eight equivalent O2- atoms.