Materials Data on U3Bi2O9 by Materials Project
U3Bi2O9 crystallizes in the tetragonal I-4m2 space group. The structure is three-dimensional. there are two inequivalent U4+ sites. In the first U4+ site, U4+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of U–O bond distances ranging from 2.21–2.42 Å. In the second U4+ site, U4+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are four shorter (2.31 Å) and four longer (2.33 Å) U–O bond lengths. Bi3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Bi–O bond distances ranging from 2.35–2.59 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent U4+ and two equivalent Bi3+ atoms to form a mixture of distorted edge and corner-sharing OU2Bi2 tetrahedra. In the second O2- site, O2- is bonded to four U4+ atoms to form a mixture of edge and corner-sharing OU4 tetrahedra. In the third O2- site, O2- is bonded to two equivalent U4+ and two equivalent Bi3+ atoms to form distorted OU2Bi2 tetrahedra that share corners with fourteen OU4 tetrahedra and edges with five OU2Bi2 tetrahedra. In the fourth O2- site, O2- is bonded to four equivalent Bi3+ atoms to form a mixture of edge and corner-sharing OBi4 tetrahedra. In the fifth O2- site, O2- is bonded to four U4+ atoms to form OU4 tetrahedra that share corners with sixteen OU4 tetrahedra and edges with six OU2Bi2 tetrahedra.