Materials Data on Cs2KU2(Si2O7)2 by Materials Project
Cs2KU2(Si2O7)2 crystallizes in the orthorhombic Cmmm space group. The structure is three-dimensional. Cs1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are four shorter (3.31 Å) and two longer (3.39 Å) Cs–O bond lengths. K1+ is bonded in a distorted q6 geometry to ten O2- atoms. All K–O bond lengths are 2.93 Å. U+4.50+ is bonded to six O2- atoms to form UO6 octahedra that share corners with two equivalent UO6 octahedra and corners with four equivalent SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 2°. There are two shorter (2.14 Å) and four longer (2.25 Å) U–O bond lengths. 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 29°. There are a spread of Si–O bond distances ranging from 1.62–1.66 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to one K1+ and two equivalent U+4.50+ atoms. In the second O2- site, O2- is bonded in a linear geometry to two equivalent Si4+ atoms. In the third O2- site, O2- is bonded in a 2-coordinate geometry to one Cs1+, one K1+, one U+4.50+, and one Si4+ atom. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Cs1+ and two equivalent Si4+ atoms.